Updated: 06/27/2017 by Computer Hope

Short for GUID Partition Table, GPT is a part of the EFI standard that defines the layout of the partition table on a hard drive. GPT is designed as an improvement to the MBR partitioning system, which has a 2.2 TB partition size limitation. GPT is part of the UEFI standard, but may also be used on older BIOS systems. Using GPT, a drive could support between 8 and 9.4 ZB, depending on the sector size.

If you're using a version of Windows that supports GPT, while setting up a drive in Disk Management, you will receive a prompt similar to the example below. Selecting GPT and clicking OK will initialize the disk as a GPT partition style.

Initializing Disk using GPT

How do I know if my hard drive is using GPT or MBR?

Use the diskpart command to determine if your drive is using a GPT or MBR.

  1. Open a Windows command line window.
  2. Type diskpart and press Enter. If a UAC prompt is displayed, click OK.
  3. At the DISKPART> prompt, type list disk and press enter. This should give you an output similar to the example below. If GPT is enabled, you have a mark under the GPT column for each drive with GPT enabled.
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 119 GB 0 B
Disk 1 Online 119 GB 119 GB
Disk 2 Online 2047 GB 0 B
Disk 3 No Media 0 B 0 B
Disk 4 No Media 0 B 0 B
Disk 5 No Media 0 B 0 B
Disk 6 No Media 0 B 0 B

GUID, Partition