5.25 in floppy disk (130 mm minifloppy) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/5-25-inch-floppy-disk-130-mm/  (CC BY 4.0)
Basis: ECMA-99, 130 mm flexible disk cartridge, 1.2 MB high density
Catalog version: 2026-10-20

Overall (mm): length 133.3, width 133.3, height 2.1
- 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. 

dimension  value
jacket side (l1)  133.3 mm ±0.4
corner angle  90° ±30′
overall thickness (e2)  over 1.2 mm, under 2.1 mm
gauge  falls 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 window  12.7 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 notches  inside 48.0 mm min. to 58.0 mm max. along the reference edge

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Ecma International: ECMA-99 (PDF) — web — Publisher's page; dimensions are facts — https://ecma-international.org/wp-content/uploads/ECMA-99_1st_edition_september_1985.pdf

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/5-25-inch-floppy-disk-130-mm/index.json
API: https://xemstudio.com/api/geometry?object=5-25-inch-floppy-disk-130-mm