Microsoft small business knowledge base

Article ID: 310561 - Last Review: October 1, 2004 - Revision: 2.1

This article was previously published under Q310561


This article describes the maximum partition size limit using the FAT16 file system in Microsoft Windows XP.


Windows XP supports the creation of primary partitions and logical drives of up to 4 gigabytes (GB) using the FAT16 file system. The maximum cluster size is 64K.

The 4-GB partition limit is imposed by the maximum number of clusters and the largest cluster size supported by the FAT file system. In Windows XP, FAT16 is limited to 64K clusters. Multiply the maximum number of clusters (64k) by the maximum cluster size (64K), and the result is 4GB. In addition to Windows XP, Microsoft Windows 2000 and Microsoft Windows NT 4.0 also support FAT16 volumes up to 4GB in size.

FAT16 volumes larger than 2GB are not accessible from computers running Microsoft Windows Millennium Edition (Me), Windows 98, Windows 95, or MS-DOS. The size limit for FAT16 volumes in these operating systems is 2 GB. In other words, to maintain compatibility with Windows Me, Windows 98, Windows 95, or MS-DOS, a volume cannot be larger than 2 GB. For additional information about FAT16 drive and partition size limits in Windows Me, Windows 98, Windows 95, and MS-DOS, click the article numbers below to view the article in the Microsoft Knowledge Base:
118335  ( ) Maximum partition size using FAT16 file system

NOTE: Windows XP, Windows 2000, Windows Me, Windows 98, and Windows 95 OEM Service Release version 2 (OSR2) support larger FAT volumes by using the FAT32 file system. For more information about the FAT32 file system, please see the following articles in the Microsoft Knowledge Base:
310525  ( ) Description of the FAT32 file system in Windows XP
154997  ( ) Description of the FAT32 File System
184006  ( ) Limitations of FAT32 file system


For additional information about converting a FAT16 or FAT32 volume to NTFS, click the following article number to view the article in the Microsoft Knowledge Base:
307881  ( ) How to convert a FAT16 volume or a FAT32 volume to an NTFS file system in Windows XP
140365  ( ) Default cluster size for FAT and NTFS

  • Microsoft Windows XP Professional
  • Microsoft Windows XP Home Edition
kbinfo KB310561
Additional support options
Ask The Microsoft Small Business Support Community
Contact Microsoft Small Business Support
Find Microsoft Small Business Support Certified Partner
Find a Microsoft Store For In-Person Small Business Support