How to change partition size in Windows 10

Updated on: May 17, 2019

This article introduces how to change partition size on Windows 10 (32 & 64 bit) without losing data. Resize disk partition with native Disk Management and partition editor software.

When system C drive is running out of space, nobody wants to start from scratch, so many people search by Google to find a better way. In technical forums, many people have similar questions such as:

  • Is it possible to change partition size in Windows 10 without reinstalling OS.
  • Is it safe to re-size partition and which tool is better to change allocated partition size.

The answer is definitely yes. To change drive size on Windows 10, there are 2 options: Windows built-in Disk Management and third party partition editor software.

Resize partition Windows 10

Change partition size with Windows 10 Disk Management

Windows 10 Disk Management inherited Shrink Volume and Extend Volume functions from previous version. Shrink Volume can decrease the size of both system C drive and data volumes. Extend Volume can increase size of a drive when there is adjacent Unallocated space. Both functions are safe to change partition size in Windows 10 (32 & 64 bit).

However, if you want to extend a volume by shrinking another one, it is impossible.

Because of many restrictions, Windows Disk Management is not the best tool to resize partitioned drives. Professional partition software is much more powerful.

How to decrease partition size:

  1. Press Windows and X on the keyboard and select Disk Management from the list.
  2. Right click the drive you want to decrease and select Shrink Volume.
  3. Enter the amount of space (1024MB=1GB) and click Shrink to execute.

This drive will be shrank within a short time in most cases.

Restrictions of Shrink Volume function:

  1. Only NTFS partition can be shrank, FAT32 and other types of volumes are not supported.
  2. Unallocated space can only be generated on the right side.
  3. Sometimes you can only shrink little space because of some unmovable files are located, even though there is large amount of free space in this drive.

Decrease partition

How to increase partition size:

Only when your disk drive configuration meet the requirements, Extend Volume is workable to increase partition size.

  1. There must be adjacent Unallocated space on the right side of the drive that you want to extend.
  2. The drive you want to extend must be NTFS, FAT32 and other types of partitions are not supported.
  3. In MBR disk, disk space of Primary or Logical partition can't be extended to Logical or Primary partition even if they are right adjacent.

To increase volume size:

  1. Right click the NTFS partition that has right adjacent Unallocated space and select Extend Volume.
  2. Simply click Next in the pop-up Extend Volume Wizard window.
  3. Click Next to use default selected disk and space, or change manually.
  4. Click Finish to execute.

Increase size

Adjust partition size with partition editor

Comparing with Windows 10 Disk Management, NIUBI Partition Editor has advantages while resizing partition, for example:

How to change partition size in Windows 10 with NIUBI:

Download NIUBI Partition Editor and you'll see all disk partitions with structure and other information. In my test computer, there are drive C, D, E and system reserved partitions.

Main window

There are two options when decrease partition size, right click this partition (here is D:) and select "Resize/Move Volume".

Option 1: drag left border towards right in the pop-up window,

Shrink D

Then Unallocated space will be produced on the left side.

Shrink D rightwards

Option 2: drag right border towards left in the pop-up window,

Shrink D

Then Unallocated space will be produced on the right side.

Shrink D lefttwards

When there is adjacent Unallocated space, you can combine it to other partitions easily.

To increase size of partition C:

Right click C and select "Resize/Move Volume" again, drag right border rightwards to combine Unallocated space.

Extend C drive

To increase size of partition E:

Right click E and select "Resize/Move Volume" again, drag left border leftwards to combine Unallocated space.

Extend E drive

If you want to decrease E to increase C, follow Option 1 to make Unallocated space on the left side of E. Before adding Unallocated into C drive, there is an additional step to move Unallocated space to left side of D.

To do this, right click drive D and select "Resize/Move Volume", drag middle position towards right in the pop-up window.

Move drive D

Take care of data while resizing disk partition

There is potential system and data damage risk while change partition size for Windows 10 computers. So you'd better back up first and use safe partitioning software. Better than other software, NIUBI Partition Editor provides powerful 1 Second Rollback, Virtual Mode and Cancel-at-well technologies to protect system and data.

Besides changing partition size, it helps you do many other operations such as: merge, convert, defrag, copy, hide, wipe and scan partition. Initialize, convert, set read-only attribute to disk, etc.