What’s the GPT Max Size in Windows Server or Windows PC?

What’s max size of GPT partition table?

GPT stands for GUID Partition Table, wherein the GUID is short for Globally Unique Identifier. Before you partition a hard drive and store data, you will be required to initialize the disk to GPT partition table, or another partition table - MBR. However, what’s the difference between those two partition tables? Is there any difference on the max size each one supports? I believe such questions puzzles many users.

In theory, a GPT disk can be up to 2^64 logical blocks in length. Logical blocks are commonly 512 bytes in size. The maximum disk size depends on the OS version. In Windows XP and the original release of Windows Server 2003, the max size of GPT disk is 2TB. For Windows Server 2003 SP1, Windows XP x64 edition, and later versions, the maximum disk size could up to 18 exabyte. In conclusion, in the new and popular operating systems such as Windows 11, Windows 10, Windows Server 2019, 2016,2012, etc, the GPT can support up to 18EB hard disk.

MBR vs GPT max size

As mentioned above, there is another partition table-MBR. So you might want to know what’s the max disk size the MBR supports. MBR is the abbreviation of Master Boot Record and it was the default partition table before hard drives were smaller than 2TB and its maximum disk size is 2TB.

Is GPT always better than MBR for the hard drive?

After knowing the max size of GPT and MBR partition size, it is easy to get that GPT has obvious advantages. However, does that mean the GPT is always a better choice than MBR at any time or situation? The answer is “NO”. Although GPT can handle up to 18EB hard drive while MBR can only support 2TB hard drive at most, MBR is still necessary in some cases:

◆If you need to install some older operating systems such as Windows XP, Vista, you have to initialize the boot hard drive to MBR since only MBR is compatible with those old OSes.

◆If you prepare to install 32-bit operating system, the disk should be of MBR partition style because only 64-bit OSes can work on GPT system disk.

On the whole, the MBR has overwhelming advantages over GPT in the OS compatibility. In most situations, the GPT is a better choice:

◆If you have a hard drive that you will use but not boot from and it is larger than 2 TB, select GPT; otherwise,only 2 TB of the large hard drive will be accessible.

◆If you have to create lots of primary partitions on the hard drive, go for GPT since MBR can only contain 4 primary partitions at most.

◆If you wish to upgrade Windows 10 to Windows 11, it is necessary to convert MBR to GPT since the UEFI is required for Windows 11.

MBR and GPT conversion without data loss

Given that there are many difference in MBR and GPT max size, OS compatibility, partition numbers, some users might want to make a conversion based on their specific requirements. Here, we would like to recommend a safe converter: AOMEI Partition Assistant Professional. It can help switch from MBR to GPT, or GPT to MBR without deleting partitions or data. If you use Disk Management or DiskPart.exe tools, you have to back up your data ahead of time to avoid data loss when you convert it.

Moreover, the recommended software can convert even a system hard drive to MBR or GPT when Windows is running, which cannot be done through Windows Disk Management. The DiskPart.exe can convert system hard drives, but you need to boot PC from installation disc and finish the conversion in WinPE mode, quite complex and time-consuming.

Now, the following part will guide you through the detailed steps of converting MBR and GPT.

Step 1. Download, install and run the software. Right-click the disk and choose “Convert to GPT”.

Step 2. Click “OK” to confirm the operation.

Step 3. Click “Apply” and “Proceed” to commit the pending operation.

This is how to convert disk to GPT. To convert to MBR, just choose “Convert to MBR Disk”. If you want to perform the operation without loading operating system, you can create a bootable media via the software first of all.

Summary

So, the GPT max disk size is 18EB in Windows 10, 8, 7 and Windows Server 2019, 2016, 2012(R2), 2008(R2). The MBR max disk size is 2TB. If you need to make a conversion after employing one of the partition table, you can use the AOMEI Partition Assistant Professional to get it done without data loss. Besides, its Server edition is developed for Windows Server 2022, 2019, 2016, 2012(R2), 2008(R2).