I was recently asked by a friend what the best file format would be formatting his USB drive. When I started to explain it, I realized that it wasn’t actually terribly self-explanatory and depending on the situation, you may want to format the drive differently.

It also depends on the size of the USB drive. For example, if it’s a small 8 GB flash drive, then it’s an easier decision than if you have a 1 TB My Book on hand.

It also depends on what operating systems you want to use the USB drive on. Is it only going to be connected to Windows machines? Or will you need to access it on Mac and Windows and be able to read/write from bother operating systems?

In this article, I’ll go through the different options that are available for formatting a USB drive and also point you to some previous posts I have written that walk you through the process step by step.

Hopefully, it’ll give you a clearer understanding of what the formats are and the advantages and disadvantages of each format.

Best File Format for USB Drive

So let’s start with the formatting dialog we all have come to know in Windows. When you right-click on a USB drive in Windows and choose Format, you get the following format dialog box:

Usb format

By default, the file system for any external USB device will be set to FAT. You can click on the drop down and choose from a couple of file systems: NTFS, FAT, FAT32, and exFAT.

File format

By default, most people end up just going with FAT and there’s a good reason why it’s set as the default. Before we get into what each format is, let’s talk about the actual options you get when trying to perform a format.

– If you try to format an internal hard disk that is smaller than 32 GB, you will see the options for NTFS, FAT and FAT32.

– If you try to format an internal hard disk that is larger than 32 GB, you will only see the option for NTFS.

– If you try to format an external USB device smaller than 32 GB, you will see all the options.

– If you try to format and external USB device larger than 32 GB, you will only see NTFS and exFAT.

Now that you know this, your final choice is much easier since you have to choose from a limited set. Now let’s talk about what each file system format accomplishes if you choose it.

File System Formats

The FAT file system is the default because it’s the most compatible file system format in the entire world. You can virtually guarantee that by using the FAT file system format, you could plug your device into any computer running any OS or plug it into any electronic or digital device and have your data readable.

If you want the most compatibility with other operating systems and hardware devices, FAT is your best choice. Obviously, you cannot use FAT or FAT32 on a USB drive that is greater than 32 GB because the FAT file system only supports up to 32 GB volumes in Windows. In addition, the max file size on a FAT file system is 4 GB.

The FAT file system is also faster and takes up less space on the USB device. However, the FAT file system has no built-in security, so anyone can read the files. FAT32 is better than FAT because it has a smaller cluster size and therefore wastes less space on the disk.

FAT32 is also more robust because it backs up the boot sector. Basically, you’re more likely to lose your data using FAT rather than FAT32. Note that FAT32 can actually support volumes up to 2 TB, but Windows restricts the size to 32 GB also like FAT. You can actually use a separate tool to format a USB drive in FAT32 that is larger than 32GB.

So when would you use NTFS? If you’re formatting a drive that is larger than 32 GB, you’ll only have the option for NTFS and exFAT. NTFS is usually only needed for internal hard drives running the Windows operating system.

It’s got a lot of extra overhead that you only need if you’re running Windows. However, if you really want the extra security, you can read my previous post on formatting USB drives with NTFS.

If you’re formatting an external USB drive, then your best choice is exFAT. What’s so great about exFAT? It’s basically a mix of the good features from NTFS and FAT. It’s got less overhead than NTFS and it gets rid of the size limits on volumes and files that are present in the FAT file system.

The major downside to exFAT is that it’s not nearly as compatible as the FAT file format. It can only be read on Windows XP and later (with service packs installed) and OS X Snow Leopard and higher. Outside of those two operating systems, there are not a ton of other systems that support the exFAT file system.

You can use exFAT on Linux, but you have to install the exFAT drivers first. If you know the system you’re going to be using the USB device on supports exFAT, then it’s the best choice because of the performance benefits and the lack of size restrictions.

Note: One piece of advice when using exFAT: if you can, format the drive on a computer running OS X. I used Windows 10 to format a drive to exFAT, but it was not readable on OS X for some reason. When I did it on OS X, it was readable on the Mac and PC. 


So to break it down and make it simple, here are you options and how you should go about formatting a USB drive. Let me know in the comments if you disagree.

1. Anything smaller than 32 GB that doesn’t require any security should be formatted in FAT or FAT32. Choose FAT32 for less disk space wastage and more reliability.

2. Anything larger than 32 GB that you know will be used with the latest operating systems for Mac and PC should be formatted in exFAT.

3. Anything larger than 32 GB that you want to be the most compatible with other devices and operating systems should be formatted in NTFS.

4. Lastly, if you are technically inclined and your drive is larger than 32GB, you can still format it in FAT32 using tools mentioned in the above linked post.

Tell us in the comments how you format your USB drives and why you chose the format you did. Enjoy!