Why can’t I format my 128GB SD card to FAT32?


FAT32 is an old file system that has size limitations which prevent you from formatting SD cards larger than 32GB. Modern SD cards that are 128GB and larger exceed this limit. Therefore, you’ll need to use a more modern file system like exFAT or NTFS when formatting your high capacity SD card.

What is FAT32?

FAT32 (File Allocation Table 32) is an older file system that was introduced in Windows 95 to replace the previous FAT16 file system. It uses 32-bit address pointers in the file allocation table, allowing it to handle larger disk sizes than FAT16, which uses 16-bit address pointers.

Some key characteristics of FAT32:

  • Compatible with all versions of Windows
  • Supported by many devices and operating systems besides Windows, like game consoles, digital cameras, etc.
  • Max volume size of 2TB
  • Max file size of 4GB
  • Slower performance than modern file systems like NTFS and exFAT

FAT32 was very popular for many years and was the default file system used for USB flash drives and other removable media. However, as storage capacities continued to increase, the limitations of FAT32 became problematic.

Why does FAT32 have size limits?

The 32-bit address pointers used by FAT32 are ultimately what restrict its maximum volume and file sizes.

A 32-bit pointer has 2^32 different values it can contain. When used for addressing, this means it can reference approximately 4 billion sectors of 512 bytes each. With some overhead for file system structures, this works out to a maximum volume size of approximately 2TB.

The 4GB limit for individual files comes from the 32-bit allocation structures used to keep track of the clusters assigned to each file. With 32-bit values, the maximum possible chain length is limited to around 4 billion clusters. At 512 bytes per cluster, that equates to the 4GB file size limit.

So in summary, the 32-bit architecture of FAT32 places hard limits on maximum volume and file sizes that cannot be exceeded. This is why FAT32 cannot work with SD cards larger than 32GB.

FAT32 volume size limits

While FAT32 can theoretically support volumes up to 2TB in size, most operating systems impose lower artificial limits on FAT32 volume sizes. This is done for compatibility reasons.

Here are some examples of maximum FAT32 volume sizes by operating system:

Operating System Max FAT32 Volume Size
Windows 98 2GB
Windows 2000 32GB
Windows XP 32GB
Windows Vista 32GB
Windows 7 32GB
Windows 8 32GB
Windows 10 32GB
Mac OS X 2TB
Linux 2TB

As you can see, Microsoft limits FAT32 volumes to 32GB maximum in modern Windows versions. This is done to discourage its use and push people towards more modern file systems.

Some operating systems like Linux and Mac OS X still allow FAT32 volumes up to 2TB. However, this is primarily done for compatibility with external drives that are already formatted with large FAT32 volumes.

So in practice, you’ll run into issues if you try to format FAT32 volumes larger than 32GB due to OS limitations. This makes FAT32 unsuitable for SD cards that are 128GB or larger.

Why can’t I format my 128GB SD card to FAT32?

Given the 32GB FAT32 volume size limits imposed by Windows and other operating systems, you cannot directly format a 128GB SD card to FAT32. The card’s capacity exceeds the limits the OS will allow.

When you try to format a large SD card with FAT32, you’ll get an error like:

“The volume is too big for FAT32.”

This is the operating system’s way of telling you the SD card size exceeds the limits it has in place for FAT32 volumes.

Some older versions of Windows like XP may allow you to format larger volumes in FAT32 if you use the command line format tool. However, this is not recommended since it can cause performance issues and system instability.

The bottom line is that 128GB SD cards are simply too large for FAT32 due to fundamental limitations in its 32-bit architecture. Some kind of size limit has to be imposed, and modern operating systems have universally chosen 32GB as the cutoff.

What file system should I use instead of FAT32?

Since FAT32 is outdated and unsuitable for larger SD cards, what are the alternatives? Here are some recommendations:


exFAT is the modern replacement for FAT32 introduced in Windows Vista. It overcomes many of the limitations of FAT32, including:

  • Volume sizes up to 128 petabytes
  • No file size limit
  • Faster performance than FAT32

exFAT is supported by newer versions of Windows, Mac OS X, and Linux. It is ideal for high capacity cards like 128GB SD cards. Almost all modern operating systems will allow you to format 128GB cards to exFAT.

The only downside to exFAT is it may not be supported on some older devices due to its newer vintage. But for most uses today, exFAT is the best cross-platform file system choice for SD cards and USB flash drives.


NTFS is the modern Windows file system introduced in Windows NT. It has no realistic limits in terms of volume or file sizes. It can easily handle a 128GB SD card.

The downside is NTFS is proprietary to Windows and read-only access on Mac OS X and Linux requires installing additional software. So it is not the most portable file system.

But if you are only using your SD card with Windows devices, NTFS is a fine option with full read/write support.

EXT4 or other Linux file systems

For Linux users, the EXT4 file system used by default in most distros is also perfectly capable of handling 128GB SD cards.

Other Linux file systems like XFS, Btrfs, etc. also work well for SD cards with large capacities. However, these may have limited support in macOS or Windows without additional software.

So in summary, the best cross platform file system for modern SD cards is exFAT. But NTFS or Linux file systems are also options if you don’t require full read/write support on all operating systems. The main thing is to avoid the outdated FAT32 file system.

How to format SD card to exFAT

Here is a quick guide on how to format your 128GB or larger SD card to exFAT on Windows, Mac OS, and Linux:


1. Insert your SD card into your computer’s card reader.
2. Open File Explorer and right-click on your SD drive. Choose “Format…”.
3. In the Format window, under File System, choose exFAT.
4. Check Quick Format and click Start to begin formatting.

Mac OS

1. Insert your SD card and open Disk Utility.
2. Select your SD card in the left sidebar and click Erase at the top.
3. Choose exFAT as the format and GUID partition scheme.
4. Click Erase to begin formatting.


1. Insert your SD card and open Gnome Disks.
2. Click the hamburger menu and choose Format Disk…
3. Under Erase, set the file system to exFAT.
4. Click Format to begin formatting.

That’s all there is to it! Just be sure to select exFAT instead of FAT32 when formatting SD cards larger than 32GB.

Can I format my 128GB SD card to FAT32?

While Windows and macOS won’t allow you to directly format a 128GB SD card to FAT32, there are some workaround methods that can force it. However, this is not recommended due to potential problems.

Here are some options for formatting FAT32 volumes larger than 32GB:

FAT32format Tool

The FAT32format tool from Ridgecrop Consultants allows you to bypass OS limits and format FAT32 volumes up to 2TB. However, this can cause performance issues and system instability. Generally only useful for compatibility with older devices.

Third-Party Formatting Tools

Some third-party formatting tools for Windows like AOMEI Partition Assistant also claim to support large FAT32 volumes. But again, this can introduce problems and is not reliable.

Linux mkfs.fat

The mkfs.fat command in Linux will format volumes to FAT32 up to 2TB in size. But you lose this formatting if you later mount the drive in Windows.


A messy workaround is partitioning cards into multiple 32GB FAT32 partitions. But this is impractical for most uses.


In summary, it is possible but not recommended to force format 128GB cards to FAT32. It will likely cause formatting to fail or introduce performance/stability issues.

You’re better off simply using a modern file system designed for this capacity like exFAT instead. This will avoid headaches!

Troubleshooting FAT32 Issues

Here are some common errors and issues that may arise when trying to format SD cards to FAT32 and how to troubleshoot them:

“Volume is too big for FAT32” Error

As discussed previously, this error occurs when trying to format a volume that exceeds the FAT32 size limits allowed by your operating system. To fix, use a smaller card or format to exFAT instead.

Poor Performance

Formatting cards larger than 32GB to FAT32 may work initially but result in slow speeds and high latency. This is caused by the excessive overhead of FAT32 managing large volumes. Switch to exFAT.

4GB File Size Limit

A properly formatted FAT32 volume will still have the 4GB file size limit. To get around this, you must use exFAT or NTFS instead.

Corrupted File System

Forcing FAT32 on large cards may sometimes result in file system corruption. You’ll have to reformat to exFAT or NTFS to correct this issue.

Windows Does Not Recognize Drive

If Windows refuses to recognize a large FAT32 volume formatted in Linux/macOS, you’ll have to reformat it to exFAT or NTFS in Windows.

In summary, avoid headaches by simply using exFAT instead of FAT32 for SD cards larger than 32GB. But if you must use FAT32, be prepared to troubleshoot performance problems and errors.

Frequently Asked Questions

Here are answers to some common questions about formatting large capacity SD cards:

Why does my 128GB SD card say it’s only 32GB after formatting to FAT32?

This is because the FAT32 format only recognizes the first 32GB due to its limits. The rest of the card capacity becomes inaccessible. You need to use exFAT instead.

Is there a way to use my 128GB card as FAT32 without limits?

Not reliably. Some tools claim to remove FAT32 limits but this tends to cause problems. exFAT is better optimized for large SD cards.

Can I split my 128GB card into multiple FAT32 partitions?

You could partition it this way but you lose the convenience of having one large volume. Most devices also don’t handle multi-partition SD cards well.

What’s the minimum card size that requires exFAT instead of FAT32?

Any card 64GB or larger should use exFAT. 32GB and lower can use FAT32 (but exFAT works too). In between, it’s a judgment call.

Is exFAT slower than FAT32? Will it reduce performance?

No, exFAT is actually faster than FAT32 on large cards. The overhead of FAT32 is what reduces performance at higher capacities.

Why do different operating systems have different FAT32 limits?

It’s primarily for backwards compatibility. Linux/Mac allow larger FAT32 volumes because they still need to interact with older media. Windows sets a 32GB limit to discourage FAT32 use.

Can I use exFAT for SD cards smaller than 128GB?

Yes, you can use exFAT even for smaller cards like 32GB or 64GB. exFAT works across the entire range of SD card sizes.


To recap, FAT32 cannot be used to format SD cards larger than 32GB due to fundamental limitations in its 32-bit architecture. Modern operating systems like Windows, macOS, and Linux all impose a 32GB size limit on FAT32 volumes.

Attempting to force FAT32 formatting on 128GB or larger SD cards is not recommended. It can result in poor performance, corruption, and system instability.

Instead, you should use the exFAT file system for SD cards bigger than 32GB. exFAT supports gigantic volume sizes up to 128PB and has no realistic file size limit. It is optimized for flash media cards and is widely supported on all major operating systems.

So if you were wondering why your 128GB or larger SD card cannot be formatted to FAT32, now you know why! The solution is simply to use exFAT instead and avoid the headaches of FAT32 limits.