How Many Partitions Does MBR Support?

How many partitions can be supported in MBR?

MBR is a partition table different from GPT. When you install Windows on a BIOS-based computer, you must use an MBR file system to format hard disks. On BIOS-based machines, Windows does not support the GUID partition table (GPT) file system.

The partition table on a disk utilizing the MBR format only holds four slots. Each can store one primary partition, or one can be used to construct an extended partition that can include an unlimited number of sub-partitions, sometimes known as "logical drives”.

So, in essence, an MBR disk can only have 4 primary partitions. If you want logical partitions, you must reduce the number of primary partitions.

In daily use, 4 partitions might be not enough for some users who may need more partitions to classify their files and programs. So, can MBR have more than 4 partitions? The answer is “Yes”. You can see, in the picture we show, the number of logical drives is unlimited, so, theoretically, you can create lots of logical drives if the disk capacity is sufficient.

Create more than 4 partitions on MBR disk

As we mentioned at end of the last part, the number of logical partitions is not restricted. If you have one or two primary partitions that you no longer want, you may convert them to logical partitions and create more partitions on the MBR drive.

In this part, we’ll show you how to convert primary partition to logical partition via Disk Management that will cause data damage, and a third-party tool to help you convert the target partitions without data loss, or if you need, create new partitions with the free space on other partition.

1. Convert a primary partition to logical partition via Disk Management

Step 1. Open Disk Management, click on one existing primary partition which you don’t need, and select “Delete Volume”.

Step 2. Right-click on the unallocated space and select “New Simple Volume”.

Step 3. Follow the New Simple Volume Wizard to create a new partition. Make sure there is enough unallocated space to create a new partition when specifying volume size.

Step 4. Then it will create a logical partition as the next partition to be created.

After it becomes a logical partition, since the number of logical partitions is unlimited, you can adjust the number of partitions.

2. Quickly create partition without delete volume

Instead of this complex procedure that requires you to wipe all of the data on the primary partition, you may turn to third-party partition manager software - AOMEI Partition Assistant Standard – to directly create a partition with the extant partition. If the primary partition you wish to split has sufficient capacity, you can directly use that space to create a new partition.

Step 1. Right-click on an existing partition as long as there is free space on the partition and select “Create Partition”. 

Step2. On the pop-out window, drag the slider to or enter an amount of space adjust the size of the partition to be created. You can also click “Advanced” to see more options such as drive letter, file system, etc.

Step3. After clicking “OK”, you can see the last partition and the newly created one becomes logical partitions automatically. If no problem, click “Apply” to execute this operation.

Then you can use the fifth partition on your MBR disk. If you wish to convert the primary partition to a logical partition but don’t want to delete data, you can use the “Convert to Logical” function.

Further reading: Convert to GPT disk to unlock more partitions

If you only need logical partitions, the methods we showed are both feasible. However, if you need more primary partitions, then you need to convert your MBR disk to a GPT disk if your device supports UEFI boot mode.

The EFI specification requires that a GUID Partition Table (GPT), which is supported by all contemporary operating systems, has a maximum of 128 partitions (all can be primary partitions) on any size hard drive. GPT is also necessary to boot from hard drives greater than 2 TB in size. This partitioning mechanism is now extensively used, with almost all new PCs natively supporting UEFI.

So, how many partitions we can create in Windows 10? If you’re using a GPT disk, in theory, you can create 128 partitions.

To do a data-safe conversion, AOMEI Partition Assistant Professional can help you. It’s the advanced edition of the Standard edition that allows users to flexibly manage their disks and partitions with more convenient features. One of all helpful functions is “Convert to GPT/MBR”. The software can recognize the partition table of the target disk, and you can convert your system disk or data disk between MBR and GPT styles without losing data.

The operations are quite simple, you just need to make sure your computer supports UEFI boot mode.

Step 1. Install and open AOMEI Partition Assistant. Right-click the system disk and select “Convert to GPT".

Step 2. Click “OK” in the pop-up window. Then, click “Yes”.

Step 3. In the main interface of AOMEI Partition Assistant, click “Apply” to start the conversion.

If the disk you converted is a system disk, you must change the boot mode from Legacy to UEFI after conversion. If you have a data drive, you may build partitions directly or divide partitions to unlock more partitions.

Conclusion

Now you know how many partitions does MBR support? If you mean primary partitions, the answer is only 4. So, we suggest you use the GPT partition style if your devices support UEFI. AOMEI Partition Assistant supports Windows 11/10/8/8.1/7/XP systems, you can totally trust this tool to organize your PC.