List of floppy disk formats

For a more in-depth textual description of some of these formats, see Floppy disk variants.

This is a list of different floppy disk formats.

8-inch, 5+1⁄4-inch, and 3+1⁄2-inch floppy disks

Physical formats

Size	Density	Sides	Tracks	tpi	bpi	Sectoring	Coercivity	Unformatted capacity per side
2 inch Video Floppy			52	256				>800 kB or 50 fields of analog video[1]
2 inch LT-1	Double		80	245
21⁄2 inch	Single		16[2][3]	48[2]				64 kB
3 inch QuickDisk
3.25 inch	Single	1	80[4]	140	4,625			250 kB
	Double				9,250			500 kB
31⁄2 inch	Single	2	40[5]	67.5	8,650	Soft	665 Oe	250 kB[citation needed]
	Double		80	135	8,717		665 Oe[6]	500 kB[citation needed]
	High		80	135	17,434		720-750 Oe	1 MB
	Extended		80	135	34,868		900 Oe	2 MB
	Triple[7]		240[8]	406.5[8]	36,700[8]			6.5 MB
4 inch DemiDiskette		1[9]
51⁄4 inch	Single/Double	2	40	48	5,876	Soft or hard	300 Oe	250 kB
	Quad		77	100			300 Oe	500 kB (Micropolis-compatible)
	Quad		80	96	5,922		300 Oe	500 kB
	High		80	96	9,646	Soft	600 Oe	833 kB
	EH[10]		104	125	29,560			6.5 MB[11]
51⁄4 inch Apple FileWare	Double	2	80	62.5		Soft		851 kiB[12]
8 inch	Single		77	48	3,268-3,408	Soft or hard (inner edge)	300 Oe	1 MB
	Double				6,816			1 MB
	HD[13]		154	96	20,560		600 Oe	9.6 MB[14]
8 inch Memorex FD	650	1[15]	50[15]		2,400	Hard (outer edge)		1.5 Mb[15]
	651		64[16]		3,100			2.5 Mb[16][17]
8 inch Burroughs	Double	2	139	150	7,100			2[18]

Logical formats

Throughout the 1970s and 1980s, many different logical disk formats were used, depending on the hardware platform.

Common floppy disk formats, logical characteristics by platform

Platform	Size	Density	Sides	Tracks/ side	Sectors/ track	Bytes/ sector	Sectoring	Capacity	rpm	Encoding	Note
Acorn	51⁄4 inch	Single	1	40	10	256	Soft	100 kB	300	FM
				80				200 kB
		Double	1	40	16	256		160 kB		MFM
				80				320 kB
			2					640 kB
	31⁄2 inch	Double	2	80	16	256		640 kB	300	MFM	Format L: MOS (Electron, Master Compact)
					5	1024		800 kB			Format D: Arthur, RISC iX Format E: RISC OS
		High			10			1,600 kB			Format F: RISC OS 3 and later. Archimedes models before the A5000 require an upgraded floppy drive.
Agat	51⁄4 inch	Double	2	80	21	256		840 kB	300	MFM	[NB 1]
Amstrad CPC/PCW	3 inch	Double	1	40	9	512		180 kB	300	MFM	Single head drive, but double-sided floppy discs (total of 360 kB per floppy)
Amstrad PCW8512/9512	3 inch	Double	2	80	9	512		720 kB	300	MFM	720 kB mode uses both sides - ensure disc inserted correct way up.
Apple II	51⁄4 inch	Double	1	35	13	256	Soft	113.75 kB	300	GCR	[NB 2]
			1		16			140 kB
	31⁄2 inch	Double	1	80	Variable (8-12)	512		400 kB	394 - 590	GCR	[NB 3]
			2					800 kB
		High	2	80	18	512		1,440 kB	300	MFM	[NB 4]
Apple Lisa	51⁄4 inch FileWare	Double	2	46	Variable (15-22)	512	Soft	851 kB	218 - 320[19]	GCR
Apple Lisa 2/Macintosh XL, Macintosh	31⁄2 inch	Double	1	80	Variable (8-12)	512	Soft	400 kB	394 - 590	GCR
Apple Macintosh			2					800 kB
		High	2	80	18	512		1,440 kB	300	MFM
Atari 8-bit	51⁄4 inch	Single	1	40	18	128	Soft	90 kB	288	FM	[NB 5]
		Dual			26	128		130 kB		MFM
		Double			18	256		180 kB
		Double	2		18	256		360 kB	300
Atari ST/TT/Falcon	31⁄2 inch	Double	1	80	9	512	Soft	360 kB	300	MFM
			2					720 kB
		High			18			1,440 kB
Coleco ADAM	51⁄4 inch	Double	1	40	8	512	soft	160 kB	300	MFM
Commodore 64 (8-bit)	51⁄4 inch	Double	1	35	Variable (17-21) ZCAV	256	Soft	170 kB	300	GCR	[NB 6]
			2					340 kB
		Quad	1	77	Variable (23-29) ZCAV			521 kB
			2					1,042 kB
	31⁄2 inch	Double	2	80	10	512		800 kB		MFM
Commodore Amiga	51⁄4 inch	Double	2	40	11	512	Soft	440 kB[NB 7]	300	MFM	[NB 8]
		Quad		80				880 kB[NB 9]
	31⁄2 inch	Double						880 kB
		High			19			1,520 kB		GCR	[NB 10]
					22			1,760 kB	150	MFM	[NB 8]
Commodore 900	51⁄4 inch	High	2	80	13-16	512	Soft	1,200kB	?	GCR	https://vintagecomputer.ca/files/Commodore/C900/C900%20Floppy%20Specification.pdf
IBM 33FD	8 inch	Single	1	77	26	128		240.5 kiB	360	FM	Diskette 1[20]
					15	256		277.5 kiB
					8	512		296 kiB
IBM 43FD			2		26	128		481 kiB			Diskette 2[20]
					15	256		555 kiB
IBM 53FD		Double			26	256		962 kiB		MFM	Diskette 2D[20]
					15	512		1.08 MiB
					8	1,024		1.16 MiB
DEC RX01	8 inch	Single	1	77	26	128		250 kB	360	FM
DEC RX02	8 inch	Double	1	77	26	256		500 kB	360	FM/MFM
DEC RX50	51⁄4 inch	Quad	1	80	10	512		400 kB	300	MFM
IBM PC compatibles[21]	8 inch	Single	1	77	26	128	Soft	250.25 kB[NB 11][21][22][23]	360	FM	[NB 12]
			2					500.5 kB[NB 11][21][22][23]
		Double	1		8	1,024		616 kB[NB 11][22][23]		MFM
			2					1,232 kB[NB 11][21][22][23]
	51⁄4 inch	Double	1	40	8	512		160 kB[NB 11]	300	MFM
			2					320 kB[NB 11]
			1		9			180 kB[NB 11]
			2					360 kB[NB 11]
		Quad[NB 13]	1	80	8			320 kB[NB 11]	300
			2					640 kB[NB 11]
		High	2	80	15			1,200 kB[NB 11]	360
	31⁄2 inch	Double	1	80	8	512		320 kB[NB 11]	300	MFM
					9			360 kB[NB 11]
			2		8			640 kB[NB 11]
					9			720 kB[NB 11]
		High			18			1,440 kB[NB 11]
					21			1,680 kB[NB 11]			DMF[NB 14]
				82				1,720 kB[NB 11]
		Extended		80	36			2,880 kB[NB 11]
MGT SAM Coupé	31⁄2 inch	Double	2	80	10	512		800 kB	300	MFM
NEC PC98	8 inch	Single	1	77	26	128		250.25 kB[NB 11]	360	FM
		Double	2	77	8	1,024		1,232 kB[NB 11]		MFM
	51⁄4 inch	Double	2	80	8	512		640 kB[NB 11]	360	MFM
					9			720 kB[NB 11]
		High			15			1,200 kB[NB 11]
				77 (80)[NB 15]	8	1,024		1,232 (1,280) kB[NB 11][NB 15]			[NB 15]
	31⁄2 inch	Double	2	80	8	512		640 kB[NB 11]	360	MFM
					9			720 kB[NB 11]
		High			15			1,200 kB[NB 11]			3-mode[NB 16][NB 15]
				77 (80)[NB 15]	8	1,024		1,232 (1,280) kB[NB 11][NB 15]
				80	18	512		1.44 MB[NB 11]	300
		Triple		240	38	512		9,120 kB	360		NEC PC-88 VA3 2TD drive only[8][7]
Osborne 1[24]	51⁄4 inch	Single	1	40	10	256	Soft	100 kB	300	FM
		Double			5	1,024		200 kB		MFM
Sega SF-7000	3 inch	Single	2	40	16	256		160 kB	?	?	Expansion unit for SC-3000 home computer. Capacity is per side. [25]
SHARP X68000	51⁄4 inch	High	2	77	8	1,024		1,232 kB[NB 11]	360	MFM
	31⁄2 inch
SHARP CE-1600F, CE-140F	21⁄2 inch[2][3]	Single	drive: 1, diskette: 2 (flippable)	16	8	512		2× 64 kB	270	GCR (4/5)	Internally based on FDU-250 Micro Floppy Disk Drive Unit[2]
Thomson	51⁄4 inch	Single	1	40	16	128		80 kB	300	FM	Thomson UD90.070
		Double	2			256		320 kB		MFM	Thomson DD90-320[NB 17]
	31⁄2 inch	Double	1	80	16	256		320 kB	300	MFM	Thomson TO9, Thomson DD09-350
		Double	2					640 kB			Thomson TO8D, TO9+, Thomson DD90-352[NB 18]
Victor 9000 / ACT Sirius 1[26]	51⁄4 inch	Single	1	80	11-19 (variable)	512		612 kB[27]	252-417 (variable)	GCR	Disks varied sectors/track and disk speed to keep consistent bit density across tracks[26]
		Double	2			512		1,196 kB[27]
Tandy TRS-80	51⁄4 inch	Single	1	35	10	256	Soft	88 kB	300	FM	Model 1/3/4
	51⁄4 inch	Double	1	40	18	256		180 kB		MFM	Model 1/3/4P
	51⁄4 inch	Double	2	40	18	256		360 kB		MFM	Model 4D
	8 inch	Double	1	77	26	256		500 kB		MFM	Model 2
	31⁄2 inch	Single	1	40	2	1,280		100 kB[28]		FM	Tandy Portable Disk Drive (aka Brother FB-100, knitking FD-19)
	31⁄2 inch	Single	1	80	2	1,280		200 kB[29]		FM	Used only in Tandy Portable Disk Drive 2
	51⁄4 inch	Double	1	35	18	256		157 kB[30]		MFM	Color Computer
HP 9114A	31⁄2 inch	Double	2	80	16	256		128-710kB[31]	600	MFM	Used with HP 110 and Portable Series 40 & 70
HP 9895A	8 inch	Double	2	77	29	256		1.18 MB[32]	360	MFM
HP 9130K	51⁄4 inch	Double	2	35	16	256		286 kB[33]	300	MFM
Burroughs MD122	8 inch	Double	2	139	44	256	Soft	6.26 MB[18]	524	MFM
Memorex 650	8 inch	Single	1	50	8	3,500 b	Hard	1.4 Mb[15]	375	FM
Memorex 651		Single		64	32	1.056 b		2.2 Mb[17]

Platform	Size	Density	Side	Track	Sector	Byte	Sectoring	Capacity	RPM	Encoding	Note
Commodore 128 (CP/M)	5 1/4	Double	2	40	26	128	Soft	260K	300	MFM	Commodore 1571
					16	256		320K
					9	512		360K
					5	1,024		400K

https://www.c64-wiki.com/wiki/Commodore_1571

https://vintagecomputer.ca/files/Commodore/C900/C900%20Floppy%20Specification.pdf

See also

• Zip drive (floppy-like, but incompatible medium using different technology)
• PocketZip (floppy-like, but incompatible medium using different technology)
• SuperDisk (floppy-like with drives also compatible with 3.5" floppy disks)
• Magneto-optical drive (floppy-like, but incompatible medium using different technology)

Notes

1. Custom controller with unique track layout.
2. 16 sector filesystems require a compatible disk controller (PROM update) and Apple DOS 3.3 or later.
3. Apple II double-density 31⁄2-inch (90 mm) drives use variable sectors sizes (tracks 00-15: 12 sectors, tracks 16-31: 11 sectors, tracks 32-47: 10 sectors, tracks 48-63: 9 sectors, tracks 64-79: 8 sectors), 394 rpm to 590 rpm.
4. Apple II high-density 31⁄2-inch (90 mm) drives require a compatible disk controller and ProDOS 8.
5. Third party drives offer up to 1440 KB.
6. Commodore floppy drives used a fixed rotation speed with variable sector density (see: Zone bit recording).
7. This format was used by the Amiga 1020 external floppy drive and some third-party drives connected to the normal Amiga floppy drive bus.
8. Though the Amiga used MFM, the format places sectors too close together for a standard IBM PC compatible floppy disk controller to read (appearing as one 5632-byte physical sector per track).
9. Format used by rare third-party drives with quad density disks; such drives were usually switchable between 80-track and 40-track (A1520/PC-compatible) operation.
10. Format used by third-party gcrdisk.device driver in order to use PC-standard HD floppy drives (which rotated at a fixed 300 rpm) via the Amiga floppy drive bus. The Amiga's floppy controller could not keep up with the data rate needed for MFM recording on HD floppies without reducing rotational speed, so the third party driver used an alternate GCR mode.
11. The calculated formatted capacity is based on FAT12 format.
12. While IBM didn't include an 8-inch floppy drive option on any of their PCs and PC DOS, MS-DOS 1.25 supported 8-inch disks and added support for higher capacities in version 2.0. MS-DOS' predecessor 86-DOS used 8-inch diskettes as well.
13. Rare format appearing on some early PC/XT clones using quad-density disks.
14. These variations are known as DMF diskettes, used for a time to pack more data on to each disk for software distribution.
15. Inner 3 tracks of 8 sectors/track format are unused.
16. The PC98 31⁄2-inch (90 mm) formats are also known as "3 Mode" floppy disks, usable on IBM PC compatibles with a 3-mode floppy drive.
17. The two sides are managed as two independent 160 KB disks
18. The two sides are managed as two independent 320 KB disks