{
 "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": "3-5-inch-floppy-disk-90-mm",
 "name": "3.5 in floppy disk (90 mm diskette)",
 "kind": "modern",
 "category": "Vintage forms",
 "group": "Retro media",
 "year": 1990,
 "question": "What are the exact dimensions of a 3.5 inch floppy disk?",
 "tags": [
  "floppy disk",
  "diskette",
  "retro media",
  "vintage computer",
  "storage"
 ],
 "aliases": [
  "3.5 floppy disk dimensions",
  "3.5 inch floppy size mm",
  "floppy disk size",
  "1.44mb floppy dimensions",
  "diskette dimensions",
  "disquete 3.5 medidas",
  "disquete 3,5 dimensões",
  "Diskette 3,5 Zoll Maße"
 ],
 "overall_mm": {
  "length": 94,
  "width": 90,
  "height": 3.3
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/3-5-inch-floppy-disk-90-mm/",
 "sheet_txt": "https://xemstudio.com/objects/3-5-inch-floppy-disk-90-mm/sheet.txt",
 "sheet": {
  "basis": "ECMA-147 (ISO/IEC 9529-1), 90 mm flexible disk cartridge, 1.44 MB high density (ISO Type 303)",
  "overall_mm": {
   "length": 94,
   "width": 90,
   "height": 3.3
  },
  "notes": [
   "A 3.5 in floppy disk case is 94.0 × 90.0 × 3.3 mm (ECMA-147 §6.1: L1 = 94.0 ±0.3 mm, L2 = 90.0 +0.4/−0.1 mm, thickness E1 = 3.3 ±0.2 mm in the 8.5 mm bands along the two edges). Three corners are R2.0 ±1.0 mm, the fourth is cut at 45° ±2°, and the case edges are rounded R0.40 ±0.25 mm.",
   "The hub access hole on side 0 is Ø26.50 mm min., centred 40.00 × 31.00 mm (±0.15) from the reference axes, which pass through the primary locating hole (Ø3.6 ±0.1 mm). The secondary locating hole is 80.0 ±0.2 mm along the X axis, 3.6 × 4.4 mm. Head windows are 9.00 ±0.20 mm wide.",
   "The file is the case at the published size: a 94.0 × 90.0 × 3.3 mm plate with R2.0 corners, no printing allowance. The 45° corner, shutter, holes and label recess are placed by the standard's figures, not its text, so they are not modelled; build around the envelope and check a real disk.",
   "ECMA-147 covers the 1.44 MB high-density disk; the 720 KB double-density disk is ECMA-125 (ISO/IEC 8860). Makers' shells may differ in shutter and label detail inside these limits — a measured Xem scan of the shutter and write-protect slide is planned."
  ],
  "table": {
   "columns": [
    "dimension",
    "value"
   ],
   "rows": [
    [
     "case length (L1)",
     "94.0 mm ±0.3"
    ],
    [
     "case width (L2)",
     "90.0 mm +0.4 / −0.1"
    ],
    [
     "thickness (E1)",
     "3.3 mm ±0.2"
    ],
    [
     "corner radius, three corners (R1)",
     "2.0 mm ±1.0"
    ],
    [
     "fourth corner",
     "45° ±2°"
    ],
    [
     "case edge radius (R2)",
     "0.40 mm ±0.25"
    ],
    [
     "hub access hole (D1)",
     "Ø26.50 mm min."
    ],
    [
     "hub hole centre from reference axes",
     "40.00 × 31.00 mm ±0.15"
    ],
    [
     "primary locating hole (D2)",
     "Ø3.6 mm ±0.1"
    ],
    [
     "secondary locating hole",
     "3.6 × 4.4 mm, 80.0 mm ±0.2 along X"
    ],
    [
     "head window width (L18)",
     "9.00 mm ±0.20"
    ],
    [
     "label area",
     "L11 3.5 mm min., L12 76.5 mm max."
    ]
   ]
  }
 },
 "sheet_text": "3.5 in floppy disk (90 mm diskette) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/3-5-inch-floppy-disk-90-mm/  (CC BY 4.0)\nBasis: ECMA-147 (ISO/IEC 9529-1), 90 mm flexible disk cartridge, 1.44 MB high density (ISO Type 303)\nCatalog version: 2026-10-20\n\nOverall (mm): length 94.0, width 90.0, height 3.3\n- A 3.5 in floppy disk case is 94.0 × 90.0 × 3.3 mm (ECMA-147 §6.1: L1 = 94.0 ±0.3 mm, L2 = 90.0 +0.4/−0.1 mm, thickness E1 = 3.3 ±0.2 mm in the 8.5 mm bands along the two edges). Three corners are R2.0 ±1.0 mm, the fourth is cut at 45° ±2°, and the case edges are rounded R0.40 ±0.25 mm.\n- The hub access hole on side 0 is Ø26.50 mm min., centred 40.00 × 31.00 mm (±0.15) from the reference axes, which pass through the primary locating hole (Ø3.6 ±0.1 mm). The secondary locating hole is 80.0 ±0.2 mm along the X axis, 3.6 × 4.4 mm. Head windows are 9.00 ±0.20 mm wide.\n- The file is the case at the published size: a 94.0 × 90.0 × 3.3 mm plate with R2.0 corners, no printing allowance. The 45° corner, shutter, holes and label recess are placed by the standard's figures, not its text, so they are not modelled; build around the envelope and check a real disk.\n- ECMA-147 covers the 1.44 MB high-density disk; the 720 KB double-density disk is ECMA-125 (ISO/IEC 8860). Makers' shells may differ in shutter and label detail inside these limits — a measured Xem scan of the shutter and write-protect slide is planned.\n\ndimension  value\ncase length (L1)  94.0 mm ±0.3\ncase width (L2)  90.0 mm +0.4 / −0.1\nthickness (E1)  3.3 mm ±0.2\ncorner radius, three corners (R1)  2.0 mm ±1.0\nfourth corner  45° ±2°\ncase edge radius (R2)  0.40 mm ±0.25\nhub access hole (D1)  Ø26.50 mm min.\nhub hole centre from reference axes  40.00 × 31.00 mm ±0.15\nprimary locating hole (D2)  Ø3.6 mm ±0.1\nsecondary locating hole  3.6 × 4.4 mm, 80.0 mm ±0.2 along X\nhead window width (L18)  9.00 mm ±0.20\nlabel area  L11 3.5 mm min., L12 76.5 mm max.\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Ecma International: ECMA-147: 90 mm flexible disk cartridges, ISO Type 303 (PDF) — web — Publisher's page; dimensions are facts — https://ecma-international.org/wp-content/uploads/ECMA-147_1st_edition_december_1990.pdf\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/3-5-inch-floppy-disk-90-mm/index.json\nAPI: https://xemstudio.com/api/geometry?object=3-5-inch-floppy-disk-90-mm\n",
 "sources": [
  {
   "publisher": "Ecma International",
   "title": "ECMA-147: 90 mm flexible disk cartridges, ISO Type 303 (PDF)",
   "url": "https://ecma-international.org/wp-content/uploads/ECMA-147_1st_edition_december_1990.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "5-25-inch-floppy-disk-130-mm",
  "8-inch-floppy-disk-200-mm",
  "cd-dvd-discs"
 ],
 "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": "How big is a 3.5 inch floppy disk?",
   "a": "94.0 × 90.0 × 3.3 mm (ECMA-147): three R2.0 corners and one 45° corner."
  },
  {
   "q": "Is a 3.5 inch floppy really 3.5 inches?",
   "a": "No: the disk inside is 90 mm; the case is 94.0 × 90.0 mm (3.70 × 3.54 in)."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "3-5-inch-floppy-disk-90-mm-case",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/3-5-inch-floppy-disk-90-mm/3-5-inch-floppy-disk-90-mm-case.step",
   "stl": "https://xemstudio.com/files/hardware/3-5-inch-floppy-disk-90-mm/3-5-inch-floppy-disk-90-mm-case.stl",
   "note": "Case 94.0 × 90.0 × 3.3 mm, R2.0 corners (ECMA-147 nominal; shutter and holes not modelled)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/3-5-inch-floppy-disk-90-mm/index.md"
}