{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "spur-gears-module-2-5",
 "name": "Spur gears, module 2.5: 10 to 80 teeth (20° involute)",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Motion",
 "year": null,
 "question": "What is the pitch diameter of a module 2.5 spur gear?",
 "tags": [
  "gear",
  "spur gear",
  "module 2.5",
  "involute"
 ],
 "aliases": [
  "module 2.5 spur gear stl",
  "m2.5 gear dimensions",
  "spur gear calculator pitch diameter",
  "involute gear step file",
  "3d printable gear"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 26,
 "url": "https://xemstudio.com/objects/spur-gears-module-2-5/",
 "sheet_txt": "https://xemstudio.com/objects/spur-gears-module-2-5/sheet.txt",
 "sheet": {
  "basis": "ISO 53 basic rack: 20° pressure angle, addendum m, dedendum 1.25 m; pitch Ø = m × teeth, tip Ø = m × (teeth + 2), root Ø = m × (teeth − 2.5)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Centre distance of two module 2.5 gears = m × (N1 + N2) / 2. Face width 20 mm, plain bore (add a hub, key or set screw to suit). Teeth below 17 are drawn without profile shift, so they undercut as real unshifted gears do."
  ],
  "table": {
   "columns": [
    "teeth",
    "pitch_dia_mm",
    "tip_dia_mm",
    "root_dia_mm",
    "face_mm",
    "bore_mm"
   ],
   "rows": [
    [
     10,
     25,
     30,
     18.75,
     20,
     7
    ],
    [
     12,
     30,
     35,
     23.75,
     20,
     8
    ],
    [
     14,
     35,
     40,
     28.75,
     20,
     10
    ],
    [
     15,
     37.5,
     42.5,
     31.25,
     20,
     11
    ],
    [
     16,
     40,
     45,
     33.75,
     20,
     12
    ],
    [
     18,
     45,
     50,
     38.75,
     20,
     14
    ],
    [
     20,
     50,
     55,
     43.75,
     20,
     15
    ],
    [
     22,
     55,
     60,
     48.75,
     20,
     17
    ],
    [
     24,
     60,
     65,
     53.75,
     20,
     19
    ],
    [
     25,
     62.5,
     67.5,
     56.25,
     20,
     20
    ],
    [
     28,
     70,
     75,
     63.75,
     20,
     22
    ],
    [
     30,
     75,
     80,
     68.75,
     20,
     24
    ],
    [
     32,
     80,
     85,
     73.75,
     20,
     25
    ],
    [
     35,
     87.5,
     92.5,
     81.25,
     20,
     25
    ],
    [
     36,
     90,
     95,
     83.75,
     20,
     25
    ],
    [
     40,
     100,
     105,
     93.75,
     20,
     25
    ],
    [
     42,
     105,
     110,
     98.75,
     20,
     25
    ],
    [
     45,
     112.5,
     117.5,
     106.25,
     20,
     25
    ],
    [
     48,
     120,
     125,
     113.75,
     20,
     25
    ],
    [
     50,
     125,
     130,
     118.75,
     20,
     25
    ],
    [
     56,
     140,
     145,
     133.75,
     20,
     25
    ],
    [
     60,
     150,
     155,
     143.75,
     20,
     25
    ],
    [
     64,
     160,
     165,
     153.75,
     20,
     25
    ],
    [
     70,
     175,
     180,
     168.75,
     20,
     25
    ],
    [
     72,
     180,
     185,
     173.75,
     20,
     25
    ],
    [
     80,
     200,
     205,
     193.75,
     20,
     25
    ]
   ]
  }
 },
 "sheet_text": "Spur gears, module 2.5: 10 to 80 teeth (20° involute) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/spur-gears-module-2-5/  (CC BY 4.0)\nBasis: ISO 53 basic rack: 20° pressure angle, addendum m, dedendum 1.25 m; pitch Ø = m × teeth, tip Ø = m × (teeth + 2), root Ø = m × (teeth − 2.5)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Centre distance of two module 2.5 gears = m × (N1 + N2) / 2. Face width 20 mm, plain bore (add a hub, key or set screw to suit). Teeth below 17 are drawn without profile shift, so they undercut as real unshifted gears do.\n\nteeth  pitch_dia_mm  tip_dia_mm  root_dia_mm  face_mm  bore_mm\n10  25.0  30.0  18.75  20.0  7\n12  30.0  35.0  23.75  20.0  8\n14  35.0  40.0  28.75  20.0  10\n15  37.5  42.5  31.25  20.0  11\n16  40.0  45.0  33.75  20.0  12\n18  45.0  50.0  38.75  20.0  14\n20  50.0  55.0  43.75  20.0  15\n22  55.0  60.0  48.75  20.0  17\n24  60.0  65.0  53.75  20.0  19\n25  62.5  67.5  56.25  20.0  20\n28  70.0  75.0  63.75  20.0  22\n30  75.0  80.0  68.75  20.0  24\n32  80.0  85.0  73.75  20.0  25\n35  87.5  92.5  81.25  20.0  25\n36  90.0  95.0  83.75  20.0  25\n40  100.0  105.0  93.75  20.0  25\n42  105.0  110.0  98.75  20.0  25\n45  112.5  117.5  106.25  20.0  25\n48  120.0  125.0  113.75  20.0  25\n50  125.0  130.0  118.75  20.0  25\n56  140.0  145.0  133.75  20.0  25\n60  150.0  155.0  143.75  20.0  25\n64  160.0  165.0  153.75  20.0  25\n70  175.0  180.0  168.75  20.0  25\n72  180.0  185.0  173.75  20.0  25\n80  200.0  205.0  193.75  20.0  25\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- ISO: ISO 53 standard basic rack (20° pressure angle, addendum 1 m, dedendum 1.25 m) and ISO 54 modules — standard — ISO; dimensions are facts [verify license at link] — https://www.iso.org/standard/5768.html\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 26 parts): https://xemstudio.com/files/hardware/spur-gears-module-2-5/index.json\nAPI: https://xemstudio.com/api/geometry?object=spur-gears-module-2-5\n",
 "sources": [
  {
   "publisher": "ISO",
   "title": "ISO 53 standard basic rack (20° pressure angle, addendum 1 m, dedendum 1.25 m) and ISO 54 modules",
   "url": "https://www.iso.org/standard/5768.html",
   "formats": [
    "standard"
   ],
   "license": "ISO; dimensions are facts",
   "license_verified": false,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "spur-gears-module-0-5",
  "spur-gears-module-0-8",
  "spur-gears-module-1",
  "spur-gears-module-1-25",
  "spur-gears-module-1-5",
  "spur-gears-involute"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. 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.",
 "mating": [],
 "faq": [
  {
   "q": "Pitch diameter of a module 2.5, 20-tooth gear?",
   "a": "50 mm; tip 55 mm."
  },
  {
   "q": "Centre distance?",
   "a": "m × (N1 + N2) / 2: a 20 and a 40 tooth module 2.5 pair sit 75 mm apart."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "gear-m2-5-10t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-10t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-10t.stl",
   "note": "module 2.5, 10 teeth: pitch Ø25, tip Ø30, root Ø18.75, face 20, bore Ø7"
  },
  {
   "file": "gear-m2-5-12t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-12t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-12t.stl",
   "note": "module 2.5, 12 teeth: pitch Ø30, tip Ø35, root Ø23.75, face 20, bore Ø8"
  },
  {
   "file": "gear-m2-5-14t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-14t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-14t.stl",
   "note": "module 2.5, 14 teeth: pitch Ø35, tip Ø40, root Ø28.75, face 20, bore Ø10"
  },
  {
   "file": "gear-m2-5-15t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-15t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-15t.stl",
   "note": "module 2.5, 15 teeth: pitch Ø37.5, tip Ø42.5, root Ø31.25, face 20, bore Ø11"
  },
  {
   "file": "gear-m2-5-16t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-16t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-16t.stl",
   "note": "module 2.5, 16 teeth: pitch Ø40, tip Ø45, root Ø33.75, face 20, bore Ø12"
  },
  {
   "file": "gear-m2-5-18t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-18t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-18t.stl",
   "note": "module 2.5, 18 teeth: pitch Ø45, tip Ø50, root Ø38.75, face 20, bore Ø14"
  },
  {
   "file": "gear-m2-5-20t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-20t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-20t.stl",
   "note": "module 2.5, 20 teeth: pitch Ø50, tip Ø55, root Ø43.75, face 20, bore Ø15"
  },
  {
   "file": "gear-m2-5-22t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-22t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-22t.stl",
   "note": "module 2.5, 22 teeth: pitch Ø55, tip Ø60, root Ø48.75, face 20, bore Ø17"
  },
  {
   "file": "gear-m2-5-24t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-24t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-24t.stl",
   "note": "module 2.5, 24 teeth: pitch Ø60, tip Ø65, root Ø53.75, face 20, bore Ø19"
  },
  {
   "file": "gear-m2-5-25t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-25t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-25t.stl",
   "note": "module 2.5, 25 teeth: pitch Ø62.5, tip Ø67.5, root Ø56.25, face 20, bore Ø20"
  },
  {
   "file": "gear-m2-5-28t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-28t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-28t.stl",
   "note": "module 2.5, 28 teeth: pitch Ø70, tip Ø75, root Ø63.75, face 20, bore Ø22"
  },
  {
   "file": "gear-m2-5-30t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-30t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-30t.stl",
   "note": "module 2.5, 30 teeth: pitch Ø75, tip Ø80, root Ø68.75, face 20, bore Ø24"
  },
  {
   "file": "gear-m2-5-32t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-32t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-32t.stl",
   "note": "module 2.5, 32 teeth: pitch Ø80, tip Ø85, root Ø73.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-35t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-35t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-35t.stl",
   "note": "module 2.5, 35 teeth: pitch Ø87.5, tip Ø92.5, root Ø81.25, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-36t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-36t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-36t.stl",
   "note": "module 2.5, 36 teeth: pitch Ø90, tip Ø95, root Ø83.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-40t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-40t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-40t.stl",
   "note": "module 2.5, 40 teeth: pitch Ø100, tip Ø105, root Ø93.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-42t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-42t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-42t.stl",
   "note": "module 2.5, 42 teeth: pitch Ø105, tip Ø110, root Ø98.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-45t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-45t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-45t.stl",
   "note": "module 2.5, 45 teeth: pitch Ø112.5, tip Ø117.5, root Ø106.25, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-48t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-48t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-48t.stl",
   "note": "module 2.5, 48 teeth: pitch Ø120, tip Ø125, root Ø113.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-50t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-50t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-50t.stl",
   "note": "module 2.5, 50 teeth: pitch Ø125, tip Ø130, root Ø118.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-56t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-56t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-56t.stl",
   "note": "module 2.5, 56 teeth: pitch Ø140, tip Ø145, root Ø133.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-60t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-60t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-60t.stl",
   "note": "module 2.5, 60 teeth: pitch Ø150, tip Ø155, root Ø143.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-64t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-64t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-64t.stl",
   "note": "module 2.5, 64 teeth: pitch Ø160, tip Ø165, root Ø153.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-70t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-70t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-70t.stl",
   "note": "module 2.5, 70 teeth: pitch Ø175, tip Ø180, root Ø168.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-72t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-72t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-72t.stl",
   "note": "module 2.5, 72 teeth: pitch Ø180, tip Ø185, root Ø173.75, face 20, bore Ø25"
  },
  {
   "file": "gear-m2-5-80t",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-80t.step",
   "stl": "https://xemstudio.com/files/hardware/spur-gears-module-2-5/gear-m2-5-80t.stl",
   "note": "module 2.5, 80 teeth: pitch Ø200, tip Ø205, root Ø193.75, face 20, bore Ø25"
  }
 ],
 "markdown": "https://xemstudio.com/objects/spur-gears-module-2-5/index.md"
}