By AOMEI / Last Updated April 15, 2021

Preface

When you are initializing a new hard drive with built-in Disk Manager in Windows 10, Windows 8/8.1, or Windows 7, a window pops up and asks you to choose between MBR (master boot record) and GPT (GUID partition table) disk. What's the difference between GPT and MBR and is there any benefit to choose one over the other?

Choose Partition Style

As known to us, a brand new hard disk must be initialized before you can partition it for data storage. So when you install a new hard drive to the computer, you will be asked to initialize the disk and choose between MBR and GPT partition style. Typically, most people would straightly click next step without knowing any of the advantages or disadvantages among MBR and GPT. And the default setting of Windows would initialize the disk to MBR partition style.

Main difference between MBR and GPT partition style

The MBR, short for Master Boot Record, is an old and commonly-used disk layout. The GPT, short for Globally Unique Identifier Partition Table, is a new disk layout associated with UEFI. Actually, MBR and GPT also determines the style of the disk. After initializing it, we can call a disk as MBR disk or GPT disk. The two different styles of disk own different schemes to manage the partitions on a disk.

Their major differences are caused by the rapid development of the information age. The older scheme (MBR) shows more and more disadvantages, so the new scheme (GPT) is introduced to fit the changes. Once a hard disk is initialized, the structured information will be recorded and stored to a particular segment of the disk. On the other hand, the information will change with the changes of partition information. So it is called partitioning scheme.

Basic MBR Disk Layout

In details, the organization of the partition table in the MBR limits the maximum addressable storage space of a disk to 2 TB (232 × 512 bytes). And it only supports up to 4 primary partitions, or 3 primary partitions and 1 extended partition combination. If you want to create more partitions, you have to make one of primary partitions as an “extended partition” and then create more logical drives within the extended partition. Otherwise, the disk will be converted to dynamic disk. It is not recommended to as you may encounter dynamic disk invalid problems and you cannot install OS on a dynamic disk.

Basic GPT Disk Layout

But with the progress of the times, larger storage devices need to be applied to the computer field. Therefore, the MBR-based partitioning scheme is in the process of being superseded by the GUID Partition Table (GPT) scheme in new computers because of GPT partition table disk supports a volume up to 2^64 blocks in length e.g. for disks with 512-byte sectors, that would be 9.44 ZB – zettabytes, and the ability to have up to 128 primary partitions. However, GPT is less compatible with operating system than MBR:

▶Windows XP 32-bit, Windows 2000, Windows NT 4, or Windows 95/98 cannot read, write, and boot from GPT disks, they will see only the Protective MBR.

▶Windows XP x64 Edition can use GPT disks for data only.

▶All versions of Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, Windows 2003 Server, Windows Server 2008 (R2), Windows Server 2012 (R2), and Windows Server 2016 can use GPT disk partition for data. Booting is only supported for 64-bit editions on UEFI-based systems.

How to check if your hard disk is MBR or GPT?

There are 2 methods to find out which partition style your hard drive is using. One is built-in graphical Disk Management tool. The other is the DiskPart command line.

Method 1. Use Disk Management Tool

Step 1. To open Windows Disk Management, press "Windows Key +R" to open the Run dialog, input "diskmgmt.msc" into the box, and click OK.

Step 2. Select the disk (here is Disk 0) you want to check. Right-click it and select "Properties".

Step 3. Select the "Volumes" tab. In "Partition style" line, you'll know whether your disk is MBR or GPT.

Check MBR or GPT DM

Except Disk Management tool, you can also check using the DiskPart utility in a Command Prompt window.

Method 2.  Use DiskPart Command Line

Step 1. To launch DiskPart utility, please click Start menu and type "diskpart" in the Search box. Right-click diskpart.exe and select "Run as administrator".

Step 2. Type "list disk" command and hit Enter. A table will display all disks connecting to your computer. If a disk is GPT, it will show an asterisk (*) under the "Gpt" column. If a disk is MBR, it will be blank under the "Gpt" column. In this example, The Disk 0 is a GPT disk, while the Disk 1 is a MBR disk.

Check MBR GPT CMD

Should I initialize disk as MBR or GPT?

After getting a basic understanding of the difference between GPT and MBR, you might wonder which one to choose when settinng up a new hard drive. In sum, if your hard drive is less than 2TB and you don’t need more than 4 primary partitions, you can choose MBR. However, if your hard drive is over 2TB and you want to create over 4 primary partitions, please switch to GPT. Besides, if your motherboard supports UEFI boot and the operating system is 64-bit, it is advised to choose GPT, otherwise, go for MBR instead.

How to make a conversion between MBR and GPT when necessary?

The major differences between GPT and MBR disk are explained elaborately above. So you can choose GPT or MBR depending on what you have and what you need to do. However, you might need to convert the current partition style from MBR to GPT or GPT to MBR. Then how to do it?

Generally speaking, you can right-click the disk in Disk Management, choose “Convert to GPT Disk” or “Convert to MBR Disk”to finish this operation. But it only works when the disk contains no partitions. That’s to say, you have to delete all existing partitions on the disk before performing the partition style. Of course, that will lead to data loss. Moreover, this method does not work if you convert the system disk since the system partition cannot be deleted within Windows.

In this situation, you can turn to the AOMEI Partition Assistant Professional. This professional partition manager can convert either data disk or system disk without deleting partitions and data. Only 3 steps can finish the conversion.

Download Free Demo Win 10/8.1/8/7/XP
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Step 1. Install and run AOMEI Partition Assistant Professional. Right click the disk (ex: the OS disk) and choose “Convert to GPT Disk”.

Convert to GPT

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

OK

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

Apply

When switching the partition style on system disk, you have to change the boot mode from Legacy BIOS to UEFI or UEFI to Legacy BIOS correspondingly.