How Do I Fully Use 4 TB or 3 TB Capacity on MBR with 2 Partitions?

Can I use 2 partitions on 3 TB MBR HDD?

The fact, you can't just use an MBR drive on a 3 TB drive, or 2 partitions on a 4 TB MBR HDD. Because MBR only supports a maximum partition size of 2 TB, and only four primary partitions can be created, while GPT disks can support the creation of more partitions with larger capacity without practical limitations.

If you want to make full use of a 3 TB or 4 TB MBR hard drive, you need to convert the MBR partition style to GPT. Therefore, it is not that 3 TB/ 4 TB MBR can't create two partitions, but MBR cannot create partitions larger than 2 TB. You need to convert 4 TB/3 TB MBR to GPT before creating two partitions

 

I am facing such a problem. I used 3 TB capacity on the MBR, but in fact, the capacity I can use is only 2 TB. Now, I want to keep the MBR partition style unchanged, but also want to use up the other 1 TB capacity and create a new partition with the unallocated space. 3 TB MBR can’t create two partitions?, if I want to use the 3 TB capacity on the MBR with two partitions, is there any way to help me achieve this goal?"

 

Two ways to convert 4 TB/3 TB MBR to GPT in Windows

There are two options to convert MBR to GPT. One is a Windows built-in tool, and the other is a third-party conversion software.

1️⃣Diskpart Command Line is an effective way to convert MBR to GPT, but it has an obvious disadvantage: you have to delete all existing partitions and data on the drive. Moreover, these command lines may be difficult to remember in a short time for users without computer background. It is easy to input the wrong disk number and lose important files.

2️⃣AOMEI Partition Assistant Standard is a disk management expert that is designed for Windows users. It provides a simple interface and operation so that all users can get a 3/4TB GPT format hard disk easily.

I will demonstrate for you one by one.

 │Way 1. Convert 4 TB/3 TB drive to GPT via third-partysoftware (data safe) 

This free and powerful partition software--AOMEI Partition Assistant Standard, is compatible with Windows 11/10/8/7. It can convert 4 TB/3 TB MBR disks into GPT disks without losing any data.

AOMEI Partition Assistant Standard can convert the data disk from MBR/GPT to GPT/MBR. If you want to convert the system disk from MBR to GPT, you need to upgrade to Professional Edition. In addition, it can also Migrate OS from GPT disk to GPT/MBR disk, realize the conversion between FAT32 and exFAT, etc.

Step 1. Install and launch Partition Assistant Standard. Right-click the hard drive you want to convert and select Convert to GPT.

Step 2. Click OK in the pop-up window to confirm the operation. Now you will find the partitioning scheme has turned into GPT. Don’t forget to click Apply to execute this task.

Step 3. Click Apply after your confirmation.

Now you can see that Disk 2 has been converted into a GPT disk, and you can create new partitions in the unallocated space.

│Way 2. Convert 4 TB/3 TB drive to GPT with Diskpart (data loss)

Diskpart can convert MBR to GPT with several lines of command. Here are the detailed steps.

Notes:
1. This method needs to clean your disk before converting, so if it is not a new hard drive or has important data on it, you have to back up the disk in advance.
2. Generally, MBR and BIOS (MBR+BIOS), GPT and UEFI (GPT+UEFI) are complementary to each other. When converting the system disk to GPT disk, please make sure that your computer motherboard supports UEFI boot mode.

Step 1. Press “WIN+R”, type “CMD” and press Enter to open the Command Prompt. Then, input "diskpart" and hit Enter.

Step 2. Type the following commands, remember to press Enter after you input each one.

● list disk
● select disk 1 (number means the drive letter, replace it with your 4 TB drive letter)
● clean (clear all partitions on the selected disk)
● convert GPT

When the “DiskPart successfully converted the selected disk to GPT format” shows on the screen, type “exit” and press “Enter” to leave the program. At this time, your partition style has been converted from MBR to GPT and the capacity has been extended.

Bonus Tip About MBR vs. GPT

Do you know what exactly are MBR and GPT? MBR (Master Boot Record) and GPT (GUID Partition Table) are two commonly used partition tables in Windows systems. The partition table is a table used to describe the partitions on the HDD or SSD and help the drive locate files so that the operating system can read the data on the drive.

But the difference is that MBR needs to use BIOS to boot, while GPT needs to use UEFI to boot. GPT has more advantages than MBR. Because GPT disks have stronger error resistance and higher security. The specific differences are shown in the following figure:

In short, GPT is better for your needs. If you want to convert MBR to GPT or GPT to MBR, you can do it all with the help of AOMEI Partition Assistant. In addition, the tool offers some extra features like checking partitions, formatting partitions, etc. to help you improve your computer performance.

Sum up

In summary, I have used two methods to solve the 3 TB/4 TB MBR two partitions for you. If you are familiar with computers, you can use Diskpart, but if you are a rookie, AOMEI Partition Assistant may be a more suitable choice.​

FAQs About How to Fully Use 4 TB or 3 TB Capacity on MBR

1. Is MBR also required for disks larger than two terabytes (TB)?

No, MBR (Master Boot Record) is not suitable for disks larger than 2 TB. MBR uses 32-bit addressing, which limits it to addressing a maximum of 2 TB of disk space. For disks larger than 2 TB, GPT (GUID Partition Table) is required.

2. How many MBR partitions can you have?

With MBR, you can have up to four primary partitions. However, if you need more than four partitions, you can create three primary partitions and one extended partition. Inside the extended partition, you can create an unlimited number of logical partitions.

3. Can I use MBR on a 3TB drive?

You can technically format a 3TB drive using MBR, but you will only be able to use 2 TB of disk space. The remaining capacity beyond 2 TB will be inaccessible. To fully utilize the 3TB drive, it's recommended to use GPT instead of MBR.