I wish to use a USB stick with both my Android device and my Windows 10 PC.

My requirements are:

  • No file size limitation
  • No root required on the Android device
  • The filesystem should be natively supported by the Android device

My Android device is a Samsung Galaxy S10. I would like a solution that would work with all modern Android devices, but I don't mind if I'm limited to the Samsung.

Which filesystem should I use?

  • Does this answer your question? How to read ext4 filesystem without mounting on a non-rooted device?
    – alecxs
    Jan 21, 2021 at 11:43
  • 3
    I would try if your Android device supports exFAT reading and writing (AOSP does not support it but most mid- to high-end device do support it). If it does support exFAT this would be my preferred file-system.
    – Robert
    Jan 21, 2021 at 12:00
  • 3
    @alecxs It's FAT that has the 4 GB limit. exFAT does not and allows file size of more than 4 GB. Jan 21, 2021 at 12:25
  • 1
    @alecxs exFAT has a file size limit of 16 Exabytes. The only disadvantage of exFAT (besides that it is not yet supported by every device) is that the clusters are getting relatively big which makes it not a good choice for storing many small files.
    – Robert
    Jan 21, 2021 at 13:29
  • 1
    Android support for exFAT is also topic in Since which Android version is exFat supported?
    – Robert
    Jan 21, 2021 at 13:39

2 Answers 2


Based on your requirements there are not many file-systems left: ext3/ext4 or exFAT both are file-systems that are natively supported nearly all Android devices.

My recommendation as file-system to use is exFAT as long as you don't want to store a large number of small files.

partitions size to cluster size:

  • 7 MB–256 MB -> cluster size 4 KB
  • 256 MB–32 GB -> cluster size 32 KB
  • 32 GB–256 TB -> cluster size 128 KB

The other option ext3/ext4 may cause problems if you ever want to connect the USB-stick to an Windows PC as Windows does not support it.

exFAT has no relevant maximum file-size (the file size limit of exFAT is 16 Exabytes and therefore larger than the largest disc for the next decades)

Regarding the exFAT support Android should support this file-system if it has an SD-card slot and supported SD-card with 64 GB and beyond. To my experience the exFAT read support usually works, but the write support can be buggy on some devices (permission problem). Therefore the only way is to format an USB-stick with exFAT and test it on the devices you want to use it.

For more details see also this question and it's answers: Since which Android version is exFat supported?


There isn't a solution that meets all of your criteria. Which criteria is your priority and where can you compromise?

If you want read-write support on both Android and Windows, you'll need to use FAT32 and format it in Windows. This will limit file size to 4 GiB.

If you need file sizes greater than 4 GiB, you can use ext3, which supports file sizes up to 2-16 TiB depending on block size. You won't have reliable write access on Windows, but there are good tools/drivers for read-only access.

In my experience, this is going to bite you eventually. Something will get corrupted if you have two different platforms writing to the same filesystem. The most reliable way to get cross-OS storage is via network-attached or cloud storage.

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