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Library › Vintage forms › Retro media · 1985 ·

5.25 in floppy disk (130 mm minifloppy)

What are the exact dimensions of a 5.25 inch floppy disk? · Modern device · basis: ECMA-99, 130 mm flexible disk cartridge, 1.2 MB high density

Also called: 5.25 floppy disk dimensions, 5 1/4 floppy size mm, minifloppy dimensions, 1.2mb floppy size, 360k floppy size, disquete 5.25 medidas, disquete 5 1/4 dimensões, Diskette 5,25 Zoll Maße

Exact dimensions. True size, with no printing tolerance added.

length
133.3 mm
width
133.3 mm
height
2.1 mm

Notes

  • A 5.25 inch floppy disk jacket is a 133.3 mm square (l1 = 133.3 ±0.4 mm, corners 90° ±30′) and between 1.2 and 2.1 mm thick overall (ECMA-99 §3.1). The central window is Ø39.7 ±0.2 mm, centred 66.65 mm from the reference edge — the middle of the jacket.
  • ECMA-99 is the 1.2 MB high-density disk; the 360 KB double-density disk is specified in ECMA-78. Write-protect notch size is not in this standard's text.
  • The file is the jacket at the published size: 133.3 × 133.3 mm, drawn 2.1 mm thick (the standard's maximum overall thickness), with the Ø39.7 mm central window at the jacket centre; no printing allowance. Index and head windows are listed above but not modelled.

5.25 in floppy disk size chart

dimensionvalue
jacket side (l1)133.3 mm ±0.4
corner angle90° ±30′
overall thickness (e2)over 1.2 mm, under 2.1 mm
gaugefalls freely through a 2.6 mm slot, 150 mm deep
central window (d1)Ø39.7 mm
central window centre (l2)66.65 mm ±0.30 from the reference edge
index window (d2)Ø6.35 mm ±0.20 at l3 42.10 / l4 60.00 mm ±0.25
head window12.7 mm ±0.2 wide × 35.00 mm ±0.25 long, R6.35 ends, lowest point 3.30 mm ±0.25 from the reference edge
optional notchesinside 48.0 mm min. to 58.0 mm max. along the reference edge

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Ecma InternationalECMA-99 (PDF)webPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json

5-25-inch-floppy-disk-130-mm-jacketJacket 133.3 mm square × 2.1 mm, Ø39.7 central window (ECMA-99 nominal)STEP · STL
Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.
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Plain text: sheet.txt · JSON: /api/geometry?object=5-25-inch-floppy-disk-130-mm

5.25 in floppy disk (130 mm minifloppy), isometric render of a generated part
Render of 5-25-inch-floppy-disk-130-mm-jacket from the free STEP; not to scale.

Fits with

3.5 in floppy disk (90 mm diskette), isometric render of a generated part
3.5 in floppy disk (90 mm diskette)94.0×90.0×3.3 mm★ 1 file
8 in floppy disk (200 mm), isometric render of a generated part
8 in floppy disk (200 mm)203.2×203.2×2.1 mm★ 1 file
CD / DVD disc Ø120 × 1.2 mm with Ø15 hole (and mini CD Ø80), isometric render of a generated part
CD / DVD disc Ø120 × 1.2 mm with Ø15 hole (and mini CD Ø80)2 sizes★ 2 files

Questions

How big is a 5.25 inch floppy disk?

The jacket is 133.3 mm square and under 2.1 mm thick, with a Ø39.7 mm centre window (ECMA-99).