File Allocation Table

File Allocation Table (FAT) Guide

Operating System	FAT16	FAT32	NTFS
Windows XP
Windows 2000
Windows NT 4.0¹
Windows 95 OSR2, Windows 98, and Windows Me
Windows 95 (prior to OSR2)
MS-DOS

Table 13.5 NTFS Size Limits

Description	Limit
Maximum file size	Theory: 16 exabytes minus 1 KB (2⁶⁴ bytes minus 1 KB) Implementation: 16 terabytes minus 64 KB (2⁴⁴ bytes minus 64 KB)
Maximum volume size	Theory: 2⁶⁴ clusters minus 1 cluster Implementation: 256 terabytes minus 64 KB ( 2³² clusters minus 1 cluster)
Files per volume	4,294,967,295 (2³² minus 1 file)

Maximum Sizes on FAT32 Volumes

A FAT32 volume must have a minimum of 65,527 clusters. Windows XP Professional can format FAT32 volumes up to 32 GB, but it can mount larger FAT32 volumes created by other operating systems. Table 13.6 lists FAT32 size limits.

Table 13.6 FAT32 Size Limits

Description	Limit
Maximum file size	4 GB minus 1 byte (2³² bytes minus 1 byte)
Maximum volume size	32 GB (implementation)
Files per volume	4,177,920
Maximum number of files and subfolders within a single folder	65,534 (The use of long file names can significantly reduce the number of available files and subfolders within a folder.)

Maximum Sizes on FAT16 Volumes

FAT16 supports a maximum of 65,524 clusters per volume. Table 13.7 lists FAT16 size limits.

Table 13.7 FAT16 Size Limits

Description	Limit
Maximum file size	4 GB minus 1 byte (2³² bytes minus 1 byte)
Maximum volume size	4 GB
Files per volume	Approximately 65,536 (2¹⁶ files)
Maximum number of files and folders within the root folder	512 (Long file names can reduce the number of available files and folders in the root folder.)

Table 13.4 Default Cluster Sizes for Volumes with Windows XP Professional File Systems

Volume Size	FAT16 Cluster Size	FAT32 Cluster Size	NTFS Cluster Size
7 MB–16 MB	2 KB	Not supported	512 bytes
17 MB–32 MB	512 bytes	Not supported	512 bytes
33 MB–64 MB	1 KB	512 bytes	512 bytes
65 MB–128 MB	2 KB	1 KB	512 bytes
129 MB–256 MB	4 KB	2 KB	512 bytes
257 MB–512 MB	8 KB	4 KB	512 bytes
513 MB–1,024 MB	16 KB	4 KB	1 KB
1,025 MB–2 GB	32 KB	4 KB	2 KB
2 GB–4 GB	64 KB	4 KB	4 KB
4 GB–8 GB	Not supported	4 KB	4 KB
8 GB–16 GB	Not supported	8 KB	4 KB
16 GB–32 GB	Not supported	16 KB	4 KB
32 GB–2 terabytes	Not supported	Not supported¹	4 KB

Options Available When You Format a Volume

Format Option	Where the Option Is Available
	Setup	My Computer or Windows Explorer	Disk Management	Format Command
Volume label	No option to create a volume label.	Available for all volumes.	Available for all volumes.	Use the /v:label parameter to specify the volume label.
Quick format	Available for all volumes.	Available for all volumes.	Available for all volumes.	Use the /q parameter to specify the quick format option.
Enable compression	No option to compress the volume.	Available for NTFS volumes.	Available for NTFS volumes.	Use the /c parameter to enable compression for NTFS volumes.
Allocation unit (cluster) size	Uses the default cluster size only.	Offers default cluster sizes for FAT volumes and clusters sizes up to 4 KB for NTFS volumes.	Offers all available cluster sizes.	Use the /a:size parameter to specify the cluster size.

BY: MRA - 06/2002