How to Repartition Hard Drive without Losing Data in Windows 11, 10, 8,7

When need to repartition a hard drive?

When you have different plans for a used hard drive, you may need to repartition it. Repartitioning a hard drive means you’ll re-allocate partition size, drive letter and file system. Generally speaking, you may want to repartition a hard drive in following situations.

▶Resize partition
A general repartition could be simply resizing existing partitions to satisfy your new need. Resize to generate unallocated space and then create new partition with that space, or add it to another space-needing partition.

▶Partition hard drive for Mac and PC Windows
It is necessary to do repartitioning if you’d like to install dual-boot operating systems. You’ll need at least two primary partitions that are large enough and formatted with different file systems to store the OS. Except for Mac and Windows, many users tend to dual boot Windows 7 and Windows XP, Windows 10 and Windows 7, etc.

▶Partition hard drive before installing Windows
You may want to partition a hard drive before you install a new operating system. Sometimes, the behavior solves the issue that the hard drive is not recognized while installing Windows.

You may need to repartition a hard disk under other situations that haven’t been listed here. However, what counts next is to figure out how to repartition a hard drive for the best.

2 General ways to repartition hard drive in Windows 11/10/8/7 

Windows brings you internal device manager that allows you to partition your hard drive in Windows 11/10/8/7. You can complete the task with the help of Disk Management or Diskpart. Let’s take a closer look at how they work.

Method 1. Repartition hard drive in Disk Management

Right click My Computer, Computer, or This PC and select Manage to open Disk Management. You’ll see partition status, drive letter, the file system used space, and other necessary factors right there.

1. To extend partition: if there is unallocated space adjacent to the partition you want to extend, you can do the extending. Right-click the partition and select Extend Volume. Follow the wizard to perform extending.

If there is no contiguous space next to that partition, or even no unallocated space on that disk, you’ll find Extend Volume grayed out.

2. To shrink partition: right-click the partition and select Shrink Volume. You should be able to shrink the partition to half the size. If you want to shrink a partition size more than a half, you need to turn to third-party software.

3. To create new partition: right-click an unallocated space and select New Simple Volume. Follow the wizard to complete the creation. You can get unallocated space by deleting existing partitions, but be sure to back up important files before you start.

If you want to repartition a hard disk completely, you can delete all existing partitions to let the unallocated space into one. Then, do the dividing and creating. Nevertheless, that can be done on the external hard drive only because Windows does not allow you to delete system partitions under the Windows environment. It also goes to formatting a partition with another file system.

Method 2. Repartition hard drive Command Prompt

You can do hard drive partitioning using CMD, a more direct method for advanced users.

Step 1. Press the Windows key + R key to open Run. Type diskpart and run as administrator.

Step 2. To resize partition, type: list volume > select volume n (where n is the number of the partition you want to change) > extend size=10240 (in MB) > exit. You can replace extend with a shrink. Each command needs to be followed by pressing "Enter".

Step 3. To format a specific partition, type: format fs=ntfs (or fat32) after you select the drive.

Tips:
▸You can type: /? to see what diskpart can do for you. Generally, more options than Disk Management can offer. For more information about diskpart.exe, check out Diskpart Windows 10.
▸To extend a partition via CMD, there must be an adjacent unallocated space right after the aim partition (same as the Disk Management), otherwise, it will fail and prompt error message.

Best way to repartition hard drive without losing data

Using Disk Management and DiskPart to repartition a hard drive in Windows PC, you can only shrink or extend the NTFS partition. Besides, the “Extend Volume” option only works when there is contiguous unallocated space on the right side of the target volume.

Moreover, all operations have the risk of losing stored data. To be specific, to give a drive with a different file system, you need to format it. To add unallocated space to a non-adjacent partition for extending, you need to delete the partition between the target partition and unallocated space.

To get around all those limitations and risks, you can switch to a professional disk partition manager named AOMEI Partition Assistant Professional (Windows 10/8/7/XP/Vista supported). It allows you to:
▸ allocate free space from one partition to another directly with no need to shrink and then extend; create a new partition directly from the existing redundant partition;
▸change file system without formatting between NTFS and FAT32;
▸quick partition a hard drive with several partitions in one click;
▸partition internal disk without booting Windows with created bootable media; and more.

You can download the demo version and check out how it resizes drives:

Opt.1. Resize Partition

Step 1. Install and run AOMEI Partition Assistant Professional. You will get the main interface. Right-click on the volume D or the drive you want to reallocate. Then, select "Resize/Move Partition".

Step 2. Drag the bar to release some free space. After that, select "OK".

With the unallocated space, you can directly create a new partition: Right-click the unallocated space and select "Create partition" and follow the prompts.

Opt.2. Move Partition

You can also use that unallocated space to extend another partition like a C drive. To do so, you can first move the D partition to the right side to make unallocated space contiguous and behind the C drive, and then add it into the C partition:

Step 1. Right click D drive and select "Resize/Move Partition", move it to the right side to make unallocated space next to C drive.

Step 2. Then right-click C drive and select "Resize Partition". Drag the bar to the right side to add into the unallocated space.

Step 3. Back to the main interface, click "Apply" to commit the pending operation.

Opt.3. Merge Partitions

With this handy tool, you can also merge non-adjacent unallocated space into another partition directly no matter where it is located on the disk or merge two neighboring partitions into one via the "Merge Partitions" feature.

Step 1. Right-click the partition you need to merge (e.g. Partition D) and choose “Advanced” and select “Merge Partition”.

Step 2. Choose the partition that you need to be merged (eg. Partition E) and click OK.

Step 3. In the main interface, after confirming the operation, click Apply and Proceed to commit it.

Note: If you decide to wipe your hard drive and repartition the whole disk or you have a new hard disk that needs to be partitioned, you can go "Quick Partition" function.

Summary

Now you know how to repartition a hard drive after reading this article. We have shared 3 tools to repartition hard drive in Windows 11/10/8/7. If you want to repartition hard drive without formatting or losing data, AOMEI Partition Assistant Professional is the best choice. For users to manage hard disks and reallocate a hard drive in Windows Server 2000/2003/2008/2012/2016/2019/2022, you can use AOMEI Partition Assistant Server Edition, a server partition magic.