{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "drill-size-index-number-letter-fraction",
 "name": "Drill size chart: number #1–#80, letter A–Z, fractional 1/64–1 in and metric drills in decimal inches and mm (ASME B94.11M)",
 "kind": "standard",
 "category": "Hardware",
 "group": "Cutting tools",
 "year": null,
 "question": "What is the decimal size of a #7, #21, letter F, 'Q' or 'R' drill, and the inch / mm equivalent of fractional and metric drill sizes?",
 "tags": [
  "drill bit",
  "drill size",
  "number drill",
  "letter drill",
  "decimal equivalent",
  "drill index",
  "twist drill",
  "asme b94.11m",
  "tool"
 ],
 "aliases": [
  "number drill sizes",
  "letter drill sizes",
  "#7 drill size",
  "q drill size",
  "f drill size in decimal",
  "drill bit size chart",
  "decimal equivalent drill chart",
  "drill size in mm",
  "#21 drill size",
  "number drill chart",
  "letter drill chart",
  "5/16 drill in mm",
  "drill gauge inches to mm",
  "drill bit conversion chart"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": false,
 "free_files": 0,
 "url": "https://xemstudio.com/objects/drill-size-index-number-letter-fraction/",
 "sheet_txt": "https://xemstudio.com/objects/drill-size-index-number-letter-fraction/sheet.txt",
 "sheet": {
  "basis": "Starrett's decimal-equivalent bulletin for the number, letter and fractional drills (printed in inches), with spot checks against three other charts; mm columns are computed here (inches × 25.4); numbers only",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Drill sizes come in four series. Number drills #1 to #80 (#1 = 0.2280 in is the largest, #80 = 0.0135 in the smallest; CNCCookbook notes ASME B94.11M numbers run to #97 but sizes past #80 are seldom seen), letter drills A to Z (A = 0.2340 in to Z = 0.4130 in), fractional drills from 1/64 in in 1/64 in steps, and metric drills. The decimal inch values for the number, letter and fractional drills are the Starrett table as printed; the mm column is that inch value × 25.4 rounded to 0.001 mm (the fractional mm are the exact fraction × 25.4). The metric rows are the standard mm sizes with the inch value computed as mm ÷ 25.4.",
   "Cross-checks: Newman Tools lists #1 = 0.2280, #40 = 0.0980, #80 = 0.0135, A = 0.234, E = 0.250, Z = 0.413; Xometry lists #8 = 0.199, A = 0.234 and 3.20 mm = 0.126 in; AIMS Industrial lists #80 = 0.343 mm, #1 = 5.791 mm, A = 5.944 mm and Z = 10.490 mm. All agree with the table here. The metric block is a short list of whole and half millimetres for convenience, not every metric drill size.",
   "Use: a drill is the size of the hole it cuts only approximately. Real holes run a little over; the clearance and tap-drill tables on thread-reference-tap-drills-clearance give the drill chosen for a thread or a screw. This page is the size lookup, not a hole-fit recommendation. Not here: drill point angle, flute length series (jobber, stub, screw-machine), taps, reamers and fractional drills above 1 in.",
   "No files: a drill is not a mating geometry on its own and a plate of holes at drill sizes would be a stand-in. The hole-size gauges for specific fasteners (rivet nuts, cable glands, PEM nuts) are on their own pages."
  ],
  "table": {
   "columns": [
    "series",
    "size",
    "decimal (in)",
    "mm (computed)"
   ],
   "rows": [
    [
     "number",
     "#1",
     "0.2280",
     "5.791"
    ],
    [
     "number",
     "#2",
     "0.2210",
     "5.613"
    ],
    [
     "number",
     "#3",
     "0.2130",
     "5.410"
    ],
    [
     "number",
     "#4",
     "0.2090",
     "5.309"
    ],
    [
     "number",
     "#5",
     "0.2055",
     "5.220"
    ],
    [
     "number",
     "#6",
     "0.2040",
     "5.182"
    ],
    [
     "number",
     "#7",
     "0.2010",
     "5.105"
    ],
    [
     "number",
     "#8",
     "0.1990",
     "5.055"
    ],
    [
     "number",
     "#9",
     "0.1960",
     "4.978"
    ],
    [
     "number",
     "#10",
     "0.1935",
     "4.915"
    ],
    [
     "number",
     "#11",
     "0.1910",
     "4.851"
    ],
    [
     "number",
     "#12",
     "0.1890",
     "4.801"
    ],
    [
     "number",
     "#13",
     "0.1850",
     "4.699"
    ],
    [
     "number",
     "#14",
     "0.1820",
     "4.623"
    ],
    [
     "number",
     "#15",
     "0.1800",
     "4.572"
    ],
    [
     "number",
     "#16",
     "0.1770",
     "4.496"
    ],
    [
     "number",
     "#17",
     "0.1730",
     "4.394"
    ],
    [
     "number",
     "#18",
     "0.1695",
     "4.305"
    ],
    [
     "number",
     "#19",
     "0.1660",
     "4.216"
    ],
    [
     "number",
     "#20",
     "0.1610",
     "4.089"
    ],
    [
     "number",
     "#21",
     "0.1590",
     "4.039"
    ],
    [
     "number",
     "#22",
     "0.1570",
     "3.988"
    ],
    [
     "number",
     "#23",
     "0.1540",
     "3.912"
    ],
    [
     "number",
     "#24",
     "0.1520",
     "3.861"
    ],
    [
     "number",
     "#25",
     "0.1495",
     "3.797"
    ],
    [
     "number",
     "#26",
     "0.1470",
     "3.734"
    ],
    [
     "number",
     "#27",
     "0.1440",
     "3.658"
    ],
    [
     "number",
     "#28",
     "0.1405",
     "3.569"
    ],
    [
     "number",
     "#29",
     "0.1360",
     "3.454"
    ],
    [
     "number",
     "#30",
     "0.1285",
     "3.264"
    ],
    [
     "number",
     "#31",
     "0.1200",
     "3.048"
    ],
    [
     "number",
     "#32",
     "0.1160",
     "2.946"
    ],
    [
     "number",
     "#33",
     "0.1130",
     "2.870"
    ],
    [
     "number",
     "#34",
     "0.1110",
     "2.819"
    ],
    [
     "number",
     "#35",
     "0.1100",
     "2.794"
    ],
    [
     "number",
     "#36",
     "0.1065",
     "2.705"
    ],
    [
     "number",
     "#37",
     "0.1040",
     "2.642"
    ],
    [
     "number",
     "#38",
     "0.1015",
     "2.578"
    ],
    [
     "number",
     "#39",
     "0.0995",
     "2.527"
    ],
    [
     "number",
     "#40",
     "0.0980",
     "2.489"
    ],
    [
     "number",
     "#41",
     "0.0960",
     "2.438"
    ],
    [
     "number",
     "#42",
     "0.0935",
     "2.375"
    ],
    [
     "number",
     "#43",
     "0.0890",
     "2.261"
    ],
    [
     "number",
     "#44",
     "0.0860",
     "2.184"
    ],
    [
     "number",
     "#45",
     "0.0820",
     "2.083"
    ],
    [
     "number",
     "#46",
     "0.0810",
     "2.057"
    ],
    [
     "number",
     "#47",
     "0.0785",
     "1.994"
    ],
    [
     "number",
     "#48",
     "0.0760",
     "1.930"
    ],
    [
     "number",
     "#49",
     "0.0730",
     "1.854"
    ],
    [
     "number",
     "#50",
     "0.0700",
     "1.778"
    ],
    [
     "number",
     "#51",
     "0.0670",
     "1.702"
    ],
    [
     "number",
     "#52",
     "0.0635",
     "1.613"
    ],
    [
     "number",
     "#53",
     "0.0595",
     "1.511"
    ],
    [
     "number",
     "#54",
     "0.0550",
     "1.397"
    ],
    [
     "number",
     "#55",
     "0.0520",
     "1.321"
    ],
    [
     "number",
     "#56",
     "0.0465",
     "1.181"
    ],
    [
     "number",
     "#57",
     "0.0430",
     "1.092"
    ],
    [
     "number",
     "#58",
     "0.0420",
     "1.067"
    ],
    [
     "number",
     "#59",
     "0.0410",
     "1.041"
    ],
    [
     "number",
     "#60",
     "0.0400",
     "1.016"
    ],
    [
     "number",
     "#61",
     "0.0390",
     "0.991"
    ],
    [
     "number",
     "#62",
     "0.0380",
     "0.965"
    ],
    [
     "number",
     "#63",
     "0.0370",
     "0.940"
    ],
    [
     "number",
     "#64",
     "0.0360",
     "0.914"
    ],
    [
     "number",
     "#65",
     "0.0350",
     "0.889"
    ],
    [
     "number",
     "#66",
     "0.0330",
     "0.838"
    ],
    [
     "number",
     "#67",
     "0.0320",
     "0.813"
    ],
    [
     "number",
     "#68",
     "0.0310",
     "0.787"
    ],
    [
     "number",
     "#69",
     "0.0292",
     "0.742"
    ],
    [
     "number",
     "#70",
     "0.0280",
     "0.711"
    ],
    [
     "number",
     "#71",
     "0.0260",
     "0.660"
    ],
    [
     "number",
     "#72",
     "0.0250",
     "0.635"
    ],
    [
     "number",
     "#73",
     "0.0240",
     "0.610"
    ],
    [
     "number",
     "#74",
     "0.0225",
     "0.571"
    ],
    [
     "number",
     "#75",
     "0.0210",
     "0.533"
    ],
    [
     "number",
     "#76",
     "0.0200",
     "0.508"
    ],
    [
     "number",
     "#77",
     "0.0180",
     "0.457"
    ],
    [
     "number",
     "#78",
     "0.0160",
     "0.406"
    ],
    [
     "number",
     "#79",
     "0.0145",
     "0.368"
    ],
    [
     "number",
     "#80",
     "0.0135",
     "0.343"
    ],
    [
     "letter",
     "A",
     "0.2340",
     "5.944"
    ],
    [
     "letter",
     "B",
     "0.2380",
     "6.045"
    ],
    [
     "letter",
     "C",
     "0.2420",
     "6.147"
    ],
    [
     "letter",
     "D",
     "0.2460",
     "6.248"
    ],
    [
     "letter",
     "E",
     "0.2500",
     "6.350"
    ],
    [
     "letter",
     "F",
     "0.2570",
     "6.528"
    ],
    [
     "letter",
     "G",
     "0.2610",
     "6.629"
    ],
    [
     "letter",
     "H",
     "0.2660",
     "6.756"
    ],
    [
     "letter",
     "I",
     "0.2720",
     "6.909"
    ],
    [
     "letter",
     "J",
     "0.2770",
     "7.036"
    ],
    [
     "letter",
     "K",
     "0.2810",
     "7.137"
    ],
    [
     "letter",
     "L",
     "0.2900",
     "7.366"
    ],
    [
     "letter",
     "M",
     "0.2950",
     "7.493"
    ],
    [
     "letter",
     "N",
     "0.3020",
     "7.671"
    ],
    [
     "letter",
     "O",
     "0.3160",
     "8.026"
    ],
    [
     "letter",
     "P",
     "0.3230",
     "8.204"
    ],
    [
     "letter",
     "Q",
     "0.3320",
     "8.433"
    ],
    [
     "letter",
     "R",
     "0.3390",
     "8.611"
    ],
    [
     "letter",
     "S",
     "0.3480",
     "8.839"
    ],
    [
     "letter",
     "T",
     "0.3580",
     "9.093"
    ],
    [
     "letter",
     "U",
     "0.3680",
     "9.347"
    ],
    [
     "letter",
     "V",
     "0.3770",
     "9.576"
    ],
    [
     "letter",
     "W",
     "0.3860",
     "9.804"
    ],
    [
     "letter",
     "X",
     "0.3970",
     "10.084"
    ],
    [
     "letter",
     "Y",
     "0.4040",
     "10.262"
    ],
    [
     "letter",
     "Z",
     "0.4130",
     "10.490"
    ],
    [
     "fractional",
     "1/64 in",
     "0.0156",
     "0.397"
    ],
    [
     "fractional",
     "1/32 in",
     "0.0312",
     "0.794"
    ],
    [
     "fractional",
     "3/64 in",
     "0.0469",
     "1.191"
    ],
    [
     "fractional",
     "1/16 in",
     "0.0625",
     "1.587"
    ],
    [
     "fractional",
     "5/64 in",
     "0.0781",
     "1.984"
    ],
    [
     "fractional",
     "3/32 in",
     "0.0938",
     "2.381"
    ],
    [
     "fractional",
     "7/64 in",
     "0.1094",
     "2.778"
    ],
    [
     "fractional",
     "1/8 in",
     "0.1250",
     "3.175"
    ],
    [
     "fractional",
     "9/64 in",
     "0.1406",
     "3.572"
    ],
    [
     "fractional",
     "5/32 in",
     "0.1562",
     "3.969"
    ],
    [
     "fractional",
     "11/64 in",
     "0.1719",
     "4.366"
    ],
    [
     "fractional",
     "3/16 in",
     "0.1875",
     "4.762"
    ],
    [
     "fractional",
     "13/64 in",
     "0.2031",
     "5.159"
    ],
    [
     "fractional",
     "7/32 in",
     "0.2188",
     "5.556"
    ],
    [
     "fractional",
     "15/64 in",
     "0.2344",
     "5.953"
    ],
    [
     "fractional",
     "1/4 in",
     "0.2500",
     "6.350"
    ],
    [
     "fractional",
     "17/64 in",
     "0.2656",
     "6.747"
    ],
    [
     "fractional",
     "9/32 in",
     "0.2812",
     "7.144"
    ],
    [
     "fractional",
     "19/64 in",
     "0.2969",
     "7.541"
    ],
    [
     "fractional",
     "5/16 in",
     "0.3125",
     "7.938"
    ],
    [
     "fractional",
     "21/64 in",
     "0.3281",
     "8.334"
    ],
    [
     "fractional",
     "11/32 in",
     "0.3438",
     "8.731"
    ],
    [
     "fractional",
     "23/64 in",
     "0.3594",
     "9.128"
    ],
    [
     "fractional",
     "3/8 in",
     "0.3750",
     "9.525"
    ],
    [
     "fractional",
     "25/64 in",
     "0.3906",
     "9.922"
    ],
    [
     "fractional",
     "13/32 in",
     "0.4062",
     "10.319"
    ],
    [
     "fractional",
     "27/64 in",
     "0.4219",
     "10.716"
    ],
    [
     "fractional",
     "7/16 in",
     "0.4375",
     "11.112"
    ],
    [
     "fractional",
     "29/64 in",
     "0.4531",
     "11.509"
    ],
    [
     "fractional",
     "15/32 in",
     "0.4688",
     "11.906"
    ],
    [
     "fractional",
     "31/64 in",
     "0.4844",
     "12.303"
    ],
    [
     "fractional",
     "1/2 in",
     "0.5000",
     "12.700"
    ],
    [
     "fractional",
     "33/64 in",
     "0.5156",
     "13.097"
    ],
    [
     "fractional",
     "17/32 in",
     "0.5312",
     "13.494"
    ],
    [
     "fractional",
     "35/64 in",
     "0.5469",
     "13.891"
    ],
    [
     "fractional",
     "9/16 in",
     "0.5625",
     "14.287"
    ],
    [
     "fractional",
     "37/64 in",
     "0.5781",
     "14.684"
    ],
    [
     "fractional",
     "19/32 in",
     "0.5938",
     "15.081"
    ],
    [
     "fractional",
     "39/64 in",
     "0.6094",
     "15.478"
    ],
    [
     "fractional",
     "5/8 in",
     "0.6250",
     "15.875"
    ],
    [
     "fractional",
     "41/64 in",
     "0.6406",
     "16.272"
    ],
    [
     "fractional",
     "21/32 in",
     "0.6562",
     "16.669"
    ],
    [
     "fractional",
     "43/64 in",
     "0.6719",
     "17.066"
    ],
    [
     "fractional",
     "11/16 in",
     "0.6875",
     "17.462"
    ],
    [
     "fractional",
     "45/64 in",
     "0.7031",
     "17.859"
    ],
    [
     "fractional",
     "23/32 in",
     "0.7188",
     "18.256"
    ],
    [
     "fractional",
     "47/64 in",
     "0.7344",
     "18.653"
    ],
    [
     "fractional",
     "3/4 in",
     "0.7500",
     "19.050"
    ],
    [
     "fractional",
     "49/64 in",
     "0.7656",
     "19.447"
    ],
    [
     "fractional",
     "25/32 in",
     "0.7812",
     "19.844"
    ],
    [
     "fractional",
     "51/64 in",
     "0.7969",
     "20.241"
    ],
    [
     "fractional",
     "13/16 in",
     "0.8125",
     "20.637"
    ],
    [
     "fractional",
     "53/64 in",
     "0.8281",
     "21.034"
    ],
    [
     "fractional",
     "27/32 in",
     "0.8438",
     "21.431"
    ],
    [
     "fractional",
     "55/64 in",
     "0.8594",
     "21.828"
    ],
    [
     "fractional",
     "7/8 in",
     "0.8750",
     "22.225"
    ],
    [
     "fractional",
     "57/64 in",
     "0.8906",
     "22.622"
    ],
    [
     "fractional",
     "29/32 in",
     "0.9062",
     "23.019"
    ],
    [
     "fractional",
     "59/64 in",
     "0.9219",
     "23.416"
    ],
    [
     "fractional",
     "15/16 in",
     "0.9375",
     "23.812"
    ],
    [
     "fractional",
     "61/64 in",
     "0.9531",
     "24.209"
    ],
    [
     "fractional",
     "31/32 in",
     "0.9688",
     "24.606"
    ],
    [
     "fractional",
     "63/64 in",
     "0.9844",
     "25.003"
    ],
    [
     "fractional",
     "1 in",
     "1.0000",
     "25.400"
    ],
    [
     "metric",
     "0.5 mm",
     "0.0197",
     "0.5"
    ],
    [
     "metric",
     "1 mm",
     "0.0394",
     "1"
    ],
    [
     "metric",
     "1.5 mm",
     "0.0591",
     "1.5"
    ],
    [
     "metric",
     "2 mm",
     "0.0787",
     "2"
    ],
    [
     "metric",
     "2.5 mm",
     "0.0984",
     "2.5"
    ],
    [
     "metric",
     "3 mm",
     "0.1181",
     "3"
    ],
    [
     "metric",
     "3.5 mm",
     "0.1378",
     "3.5"
    ],
    [
     "metric",
     "4 mm",
     "0.1575",
     "4"
    ],
    [
     "metric",
     "4.5 mm",
     "0.1772",
     "4.5"
    ],
    [
     "metric",
     "5 mm",
     "0.1969",
     "5"
    ],
    [
     "metric",
     "5.5 mm",
     "0.2165",
     "5.5"
    ],
    [
     "metric",
     "6 mm",
     "0.2362",
     "6"
    ],
    [
     "metric",
     "6.5 mm",
     "0.2559",
     "6.5"
    ],
    [
     "metric",
     "7 mm",
     "0.2756",
     "7"
    ],
    [
     "metric",
     "7.5 mm",
     "0.2953",
     "7.5"
    ],
    [
     "metric",
     "8 mm",
     "0.3150",
     "8"
    ],
    [
     "metric",
     "8.5 mm",
     "0.3346",
     "8.5"
    ],
    [
     "metric",
     "9 mm",
     "0.3543",
     "9"
    ],
    [
     "metric",
     "9.5 mm",
     "0.3740",
     "9.5"
    ],
    [
     "metric",
     "10 mm",
     "0.3937",
     "10"
    ],
    [
     "metric",
     "10.5 mm",
     "0.4134",
     "10.5"
    ],
    [
     "metric",
     "11 mm",
     "0.4331",
     "11"
    ],
    [
     "metric",
     "11.5 mm",
     "0.4528",
     "11.5"
    ],
    [
     "metric",
     "12 mm",
     "0.4724",
     "12"
    ],
    [
     "metric",
     "12.5 mm",
     "0.4921",
     "12.5"
    ],
    [
     "metric",
     "13 mm",
     "0.5118",
     "13"
    ],
    [
     "metric",
     "14 mm",
     "0.5512",
     "14"
    ],
    [
     "metric",
     "15 mm",
     "0.5906",
     "15"
    ],
    [
     "metric",
     "16 mm",
     "0.6299",
     "16"
    ],
    [
     "metric",
     "17 mm",
     "0.6693",
     "17"
    ],
    [
     "metric",
     "18 mm",
     "0.7087",
     "18"
    ],
    [
     "metric",
     "19 mm",
     "0.7480",
     "19"
    ],
    [
     "metric",
     "20 mm",
     "0.7874",
     "20"
    ],
    [
     "metric",
     "22 mm",
     "0.8661",
     "22"
    ],
    [
     "metric",
     "25 mm",
     "0.9843",
     "25"
    ]
   ]
  }
 },
 "sheet_text": "Drill size chart: number #1–#80, letter A–Z, fractional 1/64–1 in and metric drills in decimal inches and mm (ASME B94.11M) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/drill-size-index-number-letter-fraction/  (sheet CC BY 4.0)\nBasis: Starrett's decimal-equivalent bulletin for the number, letter and fractional drills (printed in inches), with spot checks against three other charts; mm columns are computed here (inches × 25.4); numbers only\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Drill sizes come in four series. Number drills #1 to #80 (#1 = 0.2280 in is the largest, #80 = 0.0135 in the smallest; CNCCookbook notes ASME B94.11M numbers run to #97 but sizes past #80 are seldom seen), letter drills A to Z (A = 0.2340 in to Z = 0.4130 in), fractional drills from 1/64 in in 1/64 in steps, and metric drills. The decimal inch values for the number, letter and fractional drills are the Starrett table as printed; the mm column is that inch value × 25.4 rounded to 0.001 mm (the fractional mm are the exact fraction × 25.4). The metric rows are the standard mm sizes with the inch value computed as mm ÷ 25.4.\n- Cross-checks: Newman Tools lists #1 = 0.2280, #40 = 0.0980, #80 = 0.0135, A = 0.234, E = 0.250, Z = 0.413; Xometry lists #8 = 0.199, A = 0.234 and 3.20 mm = 0.126 in; AIMS Industrial lists #80 = 0.343 mm, #1 = 5.791 mm, A = 5.944 mm and Z = 10.490 mm. All agree with the table here. The metric block is a short list of whole and half millimetres for convenience, not every metric drill size.\n- Use: a drill is the size of the hole it cuts only approximately. Real holes run a little over; the clearance and tap-drill tables on thread-reference-tap-drills-clearance give the drill chosen for a thread or a screw. This page is the size lookup, not a hole-fit recommendation. Not here: drill point angle, flute length series (jobber, stub, screw-machine), taps, reamers and fractional drills above 1 in.\n- No files: a drill is not a mating geometry on its own and a plate of holes at drill sizes would be a stand-in. The hole-size gauges for specific fasteners (rivet nuts, cable glands, PEM nuts) are on their own pages.\n\nseries  size  decimal (in)  mm (computed)\nnumber  #1  0.2280  5.791\nnumber  #2  0.2210  5.613\nnumber  #3  0.2130  5.410\nnumber  #4  0.2090  5.309\nnumber  #5  0.2055  5.220\nnumber  #6  0.2040  5.182\nnumber  #7  0.2010  5.105\nnumber  #8  0.1990  5.055\nnumber  #9  0.1960  4.978\nnumber  #10  0.1935  4.915\nnumber  #11  0.1910  4.851\nnumber  #12  0.1890  4.801\nnumber  #13  0.1850  4.699\nnumber  #14  0.1820  4.623\nnumber  #15  0.1800  4.572\nnumber  #16  0.1770  4.496\nnumber  #17  0.1730  4.394\nnumber  #18  0.1695  4.305\nnumber  #19  0.1660  4.216\nnumber  #20  0.1610  4.089\nnumber  #21  0.1590  4.039\nnumber  #22  0.1570  3.988\nnumber  #23  0.1540  3.912\nnumber  #24  0.1520  3.861\nnumber  #25  0.1495  3.797\nnumber  #26  0.1470  3.734\nnumber  #27  0.1440  3.658\nnumber  #28  0.1405  3.569\nnumber  #29  0.1360  3.454\nnumber  #30  0.1285  3.264\nnumber  #31  0.1200  3.048\nnumber  #32  0.1160  2.946\nnumber  #33  0.1130  2.870\nnumber  #34  0.1110  2.819\nnumber  #35  0.1100  2.794\nnumber  #36  0.1065  2.705\nnumber  #37  0.1040  2.642\nnumber  #38  0.1015  2.578\nnumber  #39  0.0995  2.527\nnumber  #40  0.0980  2.489\nnumber  #41  0.0960  2.438\nnumber  #42  0.0935  2.375\nnumber  #43  0.0890  2.261\nnumber  #44  0.0860  2.184\nnumber  #45  0.0820  2.083\nnumber  #46  0.0810  2.057\nnumber  #47  0.0785  1.994\nnumber  #48  0.0760  1.930\nnumber  #49  0.0730  1.854\nnumber  #50  0.0700  1.778\nnumber  #51  0.0670  1.702\nnumber  #52  0.0635  1.613\nnumber  #53  0.0595  1.511\nnumber  #54  0.0550  1.397\nnumber  #55  0.0520  1.321\nnumber  #56  0.0465  1.181\nnumber  #57  0.0430  1.092\nnumber  #58  0.0420  1.067\nnumber  #59  0.0410  1.041\nnumber  #60  0.0400  1.016\nnumber  #61  0.0390  0.991\nnumber  #62  0.0380  0.965\nnumber  #63  0.0370  0.940\nnumber  #64  0.0360  0.914\nnumber  #65  0.0350  0.889\nnumber  #66  0.0330  0.838\nnumber  #67  0.0320  0.813\nnumber  #68  0.0310  0.787\nnumber  #69  0.0292  0.742\nnumber  #70  0.0280  0.711\nnumber  #71  0.0260  0.660\nnumber  #72  0.0250  0.635\nnumber  #73  0.0240  0.610\nnumber  #74  0.0225  0.571\nnumber  #75  0.0210  0.533\nnumber  #76  0.0200  0.508\nnumber  #77  0.0180  0.457\nnumber  #78  0.0160  0.406\nnumber  #79  0.0145  0.368\nnumber  #80  0.0135  0.343\nletter  A  0.2340  5.944\nletter  B  0.2380  6.045\nletter  C  0.2420  6.147\nletter  D  0.2460  6.248\nletter  E  0.2500  6.350\nletter  F  0.2570  6.528\nletter  G  0.2610  6.629\nletter  H  0.2660  6.756\nletter  I  0.2720  6.909\nletter  J  0.2770  7.036\nletter  K  0.2810  7.137\nletter  L  0.2900  7.366\nletter  M  0.2950  7.493\nletter  N  0.3020  7.671\nletter  O  0.3160  8.026\nletter  P  0.3230  8.204\nletter  Q  0.3320  8.433\nletter  R  0.3390  8.611\nletter  S  0.3480  8.839\nletter  T  0.3580  9.093\nletter  U  0.3680  9.347\nletter  V  0.3770  9.576\nletter  W  0.3860  9.804\nletter  X  0.3970  10.084\nletter  Y  0.4040  10.262\nletter  Z  0.4130  10.490\nfractional  1/64 in  0.0156  0.397\nfractional  1/32 in  0.0312  0.794\nfractional  3/64 in  0.0469  1.191\nfractional  1/16 in  0.0625  1.587\nfractional  5/64 in  0.0781  1.984\nfractional  3/32 in  0.0938  2.381\nfractional  7/64 in  0.1094  2.778\nfractional  1/8 in  0.1250  3.175\nfractional  9/64 in  0.1406  3.572\nfractional  5/32 in  0.1562  3.969\nfractional  11/64 in  0.1719  4.366\nfractional  3/16 in  0.1875  4.762\nfractional  13/64 in  0.2031  5.159\nfractional  7/32 in  0.2188  5.556\nfractional  15/64 in  0.2344  5.953\nfractional  1/4 in  0.2500  6.350\nfractional  17/64 in  0.2656  6.747\nfractional  9/32 in  0.2812  7.144\nfractional  19/64 in  0.2969  7.541\nfractional  5/16 in  0.3125  7.938\nfractional  21/64 in  0.3281  8.334\nfractional  11/32 in  0.3438  8.731\nfractional  23/64 in  0.3594  9.128\nfractional  3/8 in  0.3750  9.525\nfractional  25/64 in  0.3906  9.922\nfractional  13/32 in  0.4062  10.319\nfractional  27/64 in  0.4219  10.716\nfractional  7/16 in  0.4375  11.112\nfractional  29/64 in  0.4531  11.509\nfractional  15/32 in  0.4688  11.906\nfractional  31/64 in  0.4844  12.303\nfractional  1/2 in  0.5000  12.700\nfractional  33/64 in  0.5156  13.097\nfractional  17/32 in  0.5312  13.494\nfractional  35/64 in  0.5469  13.891\nfractional  9/16 in  0.5625  14.287\nfractional  37/64 in  0.5781  14.684\nfractional  19/32 in  0.5938  15.081\nfractional  39/64 in  0.6094  15.478\nfractional  5/8 in  0.6250  15.875\nfractional  41/64 in  0.6406  16.272\nfractional  21/32 in  0.6562  16.669\nfractional  43/64 in  0.6719  17.066\nfractional  11/16 in  0.6875  17.462\nfractional  45/64 in  0.7031  17.859\nfractional  23/32 in  0.7188  18.256\nfractional  47/64 in  0.7344  18.653\nfractional  3/4 in  0.7500  19.050\nfractional  49/64 in  0.7656  19.447\nfractional  25/32 in  0.7812  19.844\nfractional  51/64 in  0.7969  20.241\nfractional  13/16 in  0.8125  20.637\nfractional  53/64 in  0.8281  21.034\nfractional  27/32 in  0.8438  21.431\nfractional  55/64 in  0.8594  21.828\nfractional  7/8 in  0.8750  22.225\nfractional  57/64 in  0.8906  22.622\nfractional  29/32 in  0.9062  23.019\nfractional  59/64 in  0.9219  23.416\nfractional  15/16 in  0.9375  23.812\nfractional  61/64 in  0.9531  24.209\nfractional  31/32 in  0.9688  24.606\nfractional  63/64 in  0.9844  25.003\nfractional  1 in  1.0000  25.400\nmetric  0.5 mm  0.0197  0.5\nmetric  1 mm  0.0394  1\nmetric  1.5 mm  0.0591  1.5\nmetric  2 mm  0.0787  2\nmetric  2.5 mm  0.0984  2.5\nmetric  3 mm  0.1181  3\nmetric  3.5 mm  0.1378  3.5\nmetric  4 mm  0.1575  4\nmetric  4.5 mm  0.1772  4.5\nmetric  5 mm  0.1969  5\nmetric  5.5 mm  0.2165  5.5\nmetric  6 mm  0.2362  6\nmetric  6.5 mm  0.2559  6.5\nmetric  7 mm  0.2756  7\nmetric  7.5 mm  0.2953  7.5\nmetric  8 mm  0.3150  8\nmetric  8.5 mm  0.3346  8.5\nmetric  9 mm  0.3543  9\nmetric  9.5 mm  0.3740  9.5\nmetric  10 mm  0.3937  10\nmetric  10.5 mm  0.4134  10.5\nmetric  11 mm  0.4331  11\nmetric  11.5 mm  0.4528  11.5\nmetric  12 mm  0.4724  12\nmetric  12.5 mm  0.4921  12.5\nmetric  13 mm  0.5118  13\nmetric  14 mm  0.5512  14\nmetric  15 mm  0.5906  15\nmetric  16 mm  0.6299  16\nmetric  17 mm  0.6693  17\nmetric  18 mm  0.7087  18\nmetric  19 mm  0.7480  19\nmetric  20 mm  0.7874  20\nmetric  22 mm  0.8661  22\nmetric  25 mm  0.9843  25\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Starrett (bulletin hosted by FIU): Decimal and tap chart: number drills 80-1, letter drills A-Z, fractional drills 1/64 to 1-1/2 in, metric tap drills — web — Publisher's page; dimensions are facts — https://web.eng.fiu.edu/zicarell/EIN3390L%20DATA/Technical%20Info/Decimal%20and%20Tap%20chart_Starrett.pdf\n- Newman Tools: Decimal equivalents: fractional, number, letter and metric drill sizes (spot-check of #1, #40, #80, A, E, Z) — web — Publisher's page; dimensions are facts — https://newmantools.com/decinch.htm\n- Xometry: Standard drill sizes chart (spot-check of #8, A, 1/8, 5/16, 3.20 mm) — web — Publisher's page; dimensions are facts — https://community.xometry.com/kb/articles/723-standard-drill-sizes\n- AIMS Industrial: Drill bit metric / imperial size chart (spot-check of #80 0.343 mm, #1 5.791 mm, A 5.944 mm, Z 10.490 mm) — web — Publisher's page; dimensions are facts — https://aimsindustrial.com.au/blogs/product-guides/blog-drill-bit-metric-imperial-size-chart\n- CNCCookbook: Drill chart bit sizes: number, letter, fractional and metric series, ASME B94.11M number range — web — Publisher's page; dimensions are facts — https://www.cnccookbook.com/drill-chart-bit-sizes-decimal-number-letter-metric\n\nNo true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.\nAPI: https://xemstudio.com/api/geometry?object=drill-size-index-number-letter-fraction\n",
 "sources": [
  {
   "publisher": "Starrett (bulletin hosted by FIU)",
   "title": "Decimal and tap chart: number drills 80-1, letter drills A-Z, fractional drills 1/64 to 1-1/2 in, metric tap drills",
   "url": "https://web.eng.fiu.edu/zicarell/EIN3390L%20DATA/Technical%20Info/Decimal%20and%20Tap%20chart_Starrett.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Newman Tools",
   "title": "Decimal equivalents: fractional, number, letter and metric drill sizes (spot-check of #1, #40, #80, A, E, Z)",
   "url": "https://newmantools.com/decinch.htm",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Xometry",
   "title": "Standard drill sizes chart (spot-check of #8, A, 1/8, 5/16, 3.20 mm)",
   "url": "https://community.xometry.com/kb/articles/723-standard-drill-sizes",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "AIMS Industrial",
   "title": "Drill bit metric / imperial size chart (spot-check of #80 0.343 mm, #1 5.791 mm, A 5.944 mm, Z 10.490 mm)",
   "url": "https://aimsindustrial.com.au/blogs/product-guides/blog-drill-bit-metric-imperial-size-chart",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "CNCCookbook",
   "title": "Drill chart bit sizes: number, letter, fractional and metric series, ASME B94.11M number range",
   "url": "https://www.cnccookbook.com/drill-chart-bit-sizes-decimal-number-letter-metric",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "thread-reference-tap-drills-clearance",
  "sheet-metal-screw-pilot-holes",
  "helical-thread-inserts-din-8140",
  "wedge-anchors-simpson-strong-bolt-2",
  "rivet-nuts-flat-head"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no tolerance added)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no tolerance added. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn. Typical accuracy by process and ISO 286 fits: https://xemstudio.com/tolerances/",
 "mating": [],
 "faq": [
  {
   "q": "What is the decimal size of a #7 drill?",
   "a": "0.2010 in (5.105 mm computed)."
  },
  {
   "q": "What is the size of a letter Q drill?",
   "a": "0.3320 in (8.433 mm computed)."
  },
  {
   "q": "What is a #1 drill in mm?",
   "a": "0.2280 in = 5.791 mm."
  },
  {
   "q": "What is the smallest number drill?",
   "a": "#80, 0.0135 in (0.343 mm); #1 is the largest number drill at 0.2280 in."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/drill-size-index-number-letter-fraction/index.md"
}