Windows File Systems Compared: NTFS to ReFS

A file system decides how data is laid out on a disk: how names, folders, permissions and free space are tracked. When you format a drive, plug in a USB stick or set up a server volume, you are picking one. This guide compares the file systems you will meet on Windows (NTFS, FAT32, exFAT and ReFS), gives limits that are documented by Microsoft, and shows how to check and convert them safely. It also corrects common myths, such as “NTFS is slow” and “ReFS is only for servers”.

The four Windows file systems

NTFS

NTFS (New Technology File System) has been the default for Windows system drives since Windows NT and XP. It is a journaling file system, so after a crash it can replay a log to bring its metadata back to a consistent state. It supports file permissions (ACLs), encryption with EFS, compression, disk quotas, hard links, symbolic links, volume shadow copies and very large files and volumes. It also supports alternate data streams, which are worth knowing about from a security point of view. Windows is normally installed on NTFS, and BitLocker works on it.

FAT32

FAT32 is the old, simple file system that almost every device can read: cameras, game consoles, TVs, car stereos, firmware update tools and the UEFI system partition. It has no permissions, no journaling and, critically, a maximum file size of 4 GB minus 1 byte. Windows’s built-in graphical formatter has traditionally limited new FAT32 volumes to 32 GB (larger ones can be created with other tools, and newer Windows builds are relaxing this, so check your version). Use it only when a device demands it.

exFAT

exFAT was created for flash storage. It removes the 4 GB file limit (the theoretical limit is 16 EiB) and works on Windows, macOS and, with an in-kernel driver since Linux 5.4 (staging) and 5.7 (mainline), Linux. It has no permissions or journaling, so it is a good choice for large USB drives and SD cards that move between systems, but not for a drive you cannot afford to corrupt if it is unplugged during a write. Safely eject exFAT drives.

ReFS

ReFS (Resilient File System) was introduced with Windows Server 2012. It is designed for resilience and scale: it checksums metadata (and file data too when integrity streams are enabled), can repair damaged data when it has a redundant copy (for example on Storage Spaces), and handles very large volumes. Contrary to the old myth, ReFS is no longer server-only. It is available in Windows Server, in Windows 11 Enterprise and Pro for Workstations, and it is used for Dev Drive volumes in Windows 11. It is meant for data volumes rather than the system drive, and lacks some NTFS features (for example EFS and NTFS compression), so check the comparison page before choosing it.

Comparison table

	NTFS	FAT32	exFAT	ReFS
Max file size	Very large (up to about 8 PB in current Windows, depending on cluster size)	4 GB – 1 byte	16 EiB (theoretical)	Very large (about 35 PB)
Permissions (ACLs)	Yes	No	No	Yes
Journaling / crash safety	Yes (metadata journal)	No	No (optional transaction-safe feature, rarely used)	Yes (copy-on-write, checksums)
Encryption	EFS and BitLocker	BitLocker To Go only	BitLocker To Go only	BitLocker
Works on macOS and Linux	macOS reads only by default; Linux reads and writes (NTFS3 or ntfs-3g)	Yes	Yes	No
Best for	Windows system and data drives	Small drives, firmware, the UEFI system partition	Large USB drives and SD cards shared between systems	Servers, Storage Spaces, Dev Drive, large data volumes

The exact limits depend on Windows version and cluster size; see Microsoft’s file system comparison page linked in the sources for the current tables.

How to see which file system a drive uses

File Explorer: right-click the drive, choose Properties. The General tab shows the file system.
PowerShell: Get-Volume | Format-Table DriveLetter, FileSystemLabel, FileSystem, Size, SizeRemaining
Command prompt (administrator): fsutil fsinfo volumeinfo C: prints the file system name and flags such as whether compression and encryption are supported.

Changing a file system: convert vs format

The old guide on this page said Disk Management can “convert” a file system by formatting. That is wrong in one important way: formatting erases everything on the volume. There are two different operations:

Convert (keeps data): Windows can convert FAT or FAT32 to NTFS in place with convert D: /fs:ntfs from an administrator prompt. It cannot convert back to FAT32, and it does not convert NTFS to exFAT.
Format (erases data): to change NTFS to exFAT or FAT32, copy your files elsewhere, then format the drive with the file system you want, either in File Explorer (right-click the drive, Format) or with format E: /fs:exfat /q. Double-check the drive letter first, because this command destroys the target’s data.

Before any conversion, back up important files. A power loss during convert can damage a volume.

Which one should you choose?

Windows system drive or internal data drive: NTFS.
External drive used only with Windows: NTFS, for permissions and crash safety.
External drive or SD card shared with macOS, Linux, cameras or consoles, with files over 4 GB: exFAT.
Old devices, firmware updates, boot partitions or drives under 32 GB that must work everywhere: FAT32.
Server volumes for virtual machines, backups or large data sets with Storage Spaces: consider ReFS after reading Microsoft’s feature notes.

Common questions

Is NTFS slower than FAT32?

Not in a way most users notice. NTFS does extra bookkeeping for permissions and journaling, but it scales better with big folders and large disks. On modern hardware, the storage device is the bottleneck.

Why can’t I copy a large file to my USB drive?

The drive is almost certainly formatted as FAT32, and the file is over 4 GB. Reformat the drive as exFAT or NTFS after copying its contents elsewhere.

What about macOS and Linux file systems?

macOS uses APFS and Linux usually uses ext4 or XFS. Windows cannot read them natively, which is one reason exFAT is used for shared drives.

Keep reading

NTFS Explained: Features, Limits, Permissions and Repair — A closer look at NTFS.
exFAT vs NTFS vs APFS/HFS+ vs ext4: Which File System to Use — How other file systems compare.
NTFS Alternate Data Streams: How to Find, Read and Remove Them — An NTFS feature worth knowing about.

Windows File Systems Compared: NTFS, FAT32, exFAT and ReFS

The four Windows file systems