If you're building a PC or simply adding a new hard drive you'll need to format the hard drive. As soon as Windows (including Windows 10) detects a new, blank drive, it will ask you to initialise it and pick from these two formats:

  • MBR (Master Boot Record)
  • GPT (GUID Partition Table)

So which format should you choose - MBR or GPT? 

Master Boot Record or MBR format has been in use since the early 1980s and is widely supported, though, it’s limited to a maximum of four primary partitions with up to 2TB, a size that’s easily exceeded by many large hard drives available today.  

The GUID Partition Table (GPT) format, is a newer technology which allows much larger disks to be used up to a theoretical limit of 9.4 zettabytes (ZB), or nearly 10 billion terabytes. It has been estimated that, as of 2013, the whole of the world wide web occupies around 4ZB. Windows currently limits GPT partitions to 256TB.  

Additionally, there’s no theoretical limit to the number of partitions you can create on a GPT format drive. 

The main issues to consider are those of compatibility. Older versions of Windows, such as 32-bit XP can’t read, write or boot from GPT disks. These days Windows can handle big disks quite happily, but require you to have a modern PC which supports UEFI on the motherboard. 

If you’re using MBR format, you may also run into problems when installing multiple operating systems on a single drive. Obviously all installed operating systems must be compatible with your chosen format, but it’s also not unusual for an operating system to create multiple partitions during installation, especially if you want to install a recovery partition. Using a GPT drive should ensure that you don’t run out of available partitions. 

Another advantage of GPT over MBR is that is saves two copies of the GPT header, one at the start of the disk and one at the end. This small amount of redundancy affords some protection against data corruption when compared to MBR format which only saves a single partition table. 

So, to summarise: if you want to use a large hard drive (more than 2TB) with lots of partitions and multiple operating systems, go for GPT. Even if your drive is 2TB or below, it's still worth using GPT if your PC or laptop supports this format.

Only use MBR if you want to retain compatibility with older hardware and 32-bit versions of Windows.

Here's a complete guide on how to format a hard drive in Windows.