How to resize disk partition on Windows 10

Updated on: May 17, 2019

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

C drive running out of space issue is very common to Windows 10 computers, no matter you use desktop or laptop, SSD, mechanical disk or even RAID arrays. But to many computer users, it is not an easy task to resize Windows 10 partitions. In technical forums, many people ask similar questions such as: "is it possible to re-size disk partition without reinstalling Windows 10, my c drive is full but there is plenty in D", "Is it safe to resize my Windows 10 volumes, will it cause data damage?"

In this article I'll explain why disk partitions can be resized, and how to resize partition in Windows 10 with built-in and 3rd party tools.

Why disk partition can be re-sized?

A partition (also called as drive or volume) is just part of entire hard disk and there could be many partitions in a disk. A disk partition is used to store variety of files, including system and data files. All files are organized by File System. Take MBR style disk as example:

Disk drive

  1. Operating System read the parameters in MBR (master boot record) and then it knows how many partitions in this disk, the start and end position of each partition.
  2. From DBR of each partition, Operating System gets the list of all files in this partition including name, create date, type and additional parameters of each file.
  3. From the parameters, Operating System can locate the data area.

To change a file, Operating System simply modify the data area and then update the related parameters in DBR.

To resize a disk partition, it is much easier if it doesn't require moving location of this partition. In this case, the partition tool just modify the parameters of start and end position of this volume. But if partition moving is required, it is much more complicated, besides updating partition position, the partition tool also move location and update parameters of all file in this volume, so it cost much longer time if there are large amount of files.

Windows 10 partition resizing tools

There are two kinds of tools to resize volume on Windows 10: built-in Diskpart command or GUI Disk Management and 3rd-party partition software.

The advantage of Diskpart and Disk Management is born from Microsoft (actually provide by other company), both Shrink and Extend Volume feature can change partition size without rebooting, but meanwhile it has many limitations, which cause you cannot resize partition under some situations. It is far behind the professional partition management software.

About third party software, there are many choice, but there is one point you should know: take care of your data. Data safety is most important but there is system boot failure or data loss risk if you use some unreliable partition software.

Better than other tools, NIUBI Partition Editor provides unique 1 Second Rollback, Virtual Mode and Cancel-at-will technologies to ensure system and data intact. It also provide Hot-Resize technology to help resize disk partition without rebooting, advanced file-moving algorithm to help resize partition much faster. Besides resizing partition on Windows 10, 8, 7, Vista and XP, it helps you move, merge, copy, convert, defrag, wipe, hide, scan partition, etc.

How to resize partition in Windows 10 Disk Management:

Windows 10 Disk Management has NO "resize volume" functionality, partition resizing is realized by Shrink Volume and Extend Volume.

To shrink a volume:

  1. Press Windows and X on keyboard and select Disk Management from the list.
  2. Right click the partition and select Shrink Volume.
  3. In the pop-up window, enter the amount of space and then click Shrink to execute.

Shrink volume

To extend a volume:

  1. Right click this drive in Disk Management and select Extend Volume.
  2. Simply click Next in the pop-up Extend Volume Wizard window.
  3. Confirm the operation and click Finish to proceed.

To use Extend Volume, your disk partition configuration should meet all requirements below:

  • The drive you want to extend must be formatted as NTFS, FAT 32 and other types of partitions are not supported.
  • There must be adjacent Unallocated space behind this drive.
  • In MBR style disk, Free space in Extended partition cannot be added to Primary partition, even if it is right adjacent.

If you want to extend C drive by shrinking D, it is impossible in Disk Management. Shrink Volume can only shrink a drive (such as D:) towards left and make Unallocated space on the right side, but to extend C drive with Extend Volume, Unallocated space must be on the left side of D. This is the reason why many people feedback that Extend Volume is greyed out.

Extend Volume greyed

As you see, Extend Volume is also disabled for E drive, because Unallocated space is on its left side.

Resize Window 10 volume with professional software

With professional partition software, both NTFS and FAT32 partition are supported. Unallocated space can be generated on either side when shrinking. You can extend a drive with Unallocated space or free space inside of any other volume in the same disk no matter these space are adjacent or not.

Download NIUBI Partition Editor, you'll see all disk partitions with structure and detailed info on the right, available operations to the highlighted disk or partition are listed on the left side.

NIUBI Partition Editor

How to resize Windows 10 partition with NIUBI:

Right click a partition (here is D:) and select "Resize/Move Volume", you have two options in the pop-up window.

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

Shrink D

Then partition D is resized and 20GB Unallocated space is made on its left.

Shrink D rightwards

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

Shrink D

Then Unallocated space will be made on the right side of drive D.

Shrink D lefttwards

If you want to resize and extend partition C, follow Option 1 above to make Unallocated space on the left side of D. Then right click drive C and select "Resize/Move Volume" again, drag right border rightwards to combine the Unallocated space.

Extend C drive

Resize partition C

This software is designed to work in its own virtual mode, the operations you do will be listed as pending on bottom left. To resize real disk partitions, you need to click Apply on top left to confirm and execute.

Similarly, if you want to resize and extend partition E, follow Option 2 above to make Unallocated space on the right side of D. Then right click drive E: and select "Resize/Move Volume" again, drag left border leftwards to combine the Unallocated space.

Extend E drive

Resize partition E

If you want to resize partition E to expand C, follow the steps below:

  1. Shrink drive E: and make Unallocated space on the left side.
  2. Move Unallocated space from right side of drive D: to the left.
  3. Add Unallocated space into C drive.

To move Unallocated space from right to the left, right click drive D: and select "Resize/Move Volume", drag middle position rightwards in the pop-up window:

Move drive D

Watch the video guide how to resize disk partition on Windows 10:

Video guide

NO partitioning software can resize partition beyond separated hard disk. If there is no other volume or not enough free space in other partitions in the same disk, you can clone disk to another large one with NIUBI. While cloning, you can resize partitions with extra disk space.