How to resize Windows 10 partition without losing data

by John, Updated on: March 1, 2021

This article introduces how to resize partition in Windows 10 (32 & 64 bit) without losing data or reinstalling OS/programs. Resize volume with Windows 10 Disk Management and free partition editor.

C drive out of space is common issue in Windows 10 computers, no matter you use desktop or laptop, SSD, mechanical disk or even RAID arrays. The fast way to solve this problem is resizing partitions to increase C drive free space, 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 OS, my c drive is full but there is plenty in D", "Is it safe to resize my Windows 10 drives, 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 Disk Management tool and free partition editor software.

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. Many people use partition C for Operating System, create separate partitions for programs and personal files. Before saving files to a partition, it must be formatted with a file system. The common file system in Windows computer is FAT32 and NTFS. 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, and the start/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 many other 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 associated parameters in DBR.

To resize partition in Windows 10 computer, it is much easier if it doesn't require moving files of this partition. In this case, the partition tool just modify the parameters of start and end position of this volume. But if file 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 in Windows 10: built-in Diskpart command or GUI Disk Management and 3rd-party partition manager software.

Some people like to use Windows native tools thinking they have best compatibility, but it's not true. I've encountered the issue at least 3 times that Disk Management destroyed my drives when shrinking partition. Be careful when there are many partitions including Logical drive on a disk.

Third party software is much more powerful and it's much easier to resize partition for Windows 10/8/7 computers. However, few partitioning software are safe enough. Therefore, before resizing partition, you'd better make a backup and run the safest program. Otherwise, your system and partitions may be damaged.

Better than other tools, NIUBI Partition Editor has unique 1 Second Rollback, Virtual Mode and Cancel-at-well technologies to protect system and data. In addition, it has Hot-Resize technology to help resize disk partition without rebooting and advanced file-moving algorithm to help resize partition 30% to 300% faster.

How to resize partition in Windows 10 using Disk Management:

Windows 10 Disk Management has no "resize volume" function, partition resizing is realized by Shrink Volume and Extend Volume. Note: only NTFS partition is supported. FAT32 and EFI partition can't be resized by this native tool.

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 extend partition in Windows 10 Disk Management, your disk partition layout must meet the requirements:

  1. There must be adjacent Unallocated space on the right of this drive.
  2. If there's no such space, you must delete the right partition to get contiguous Unallocated space.
  3. On MBR style disk, Free space deleted from Logical drive cannot be added to any Primary partition, even if it is right adjacent.

Windows 10 has another native tool - Diskpart to help change partition size. Diskpart is a command line tool, although it works in different way, it has same limitations with Disk Management. Learn how to extend partition with diskpart.

If you want to extend C drive by shrinking D or any other partition, it is impossible with Disk Management or diskpart command. Because, Shrink Volume can only shrink a partition (such as D:) towards left and make Unallocated space on the right side, but to extend C drive with either native tool, Unallocated space must be on the left side of D. This is the reason why Extend Volume is disabled for C drive after shrinking D.

Extend Volume greyed

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

Resize Window 10 volume with free partition software

To resize partition in Windows 10 without losing data, NIUBI Partition Editor is better choice. Both NTFS and FAT32 partition can be resized. Unallocated space can be generated on either left or right when shrinking partition. This space can be combined to any contiguous and non adjacent partitions on the same disk.

Download this program, you'll see all storage devices with partitions structure and other information on the right, available operations to the selected disk or partition are listed on the left and by right clicking.

NIUBI Partition Editor

How to resize partition in Windows 10/8/7 laptop/desktop 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 the 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 D drive.

Shrink D lefttwards

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

Extend C drive

Then two pending operations are created on bottom left, you need to click Apply on top left to take effect.

Resize partition C

If you want to extend partition E, follow Option 2 above to make Unallocated space on the right of D drive. Then right click 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 shrink E to extend non adjacent partition 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 to C drive.

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

Move drive D

Watch the video guide how to resize volume in Windows 10 (32/64 bit):

Video guide

Besides resizing partition for Windows 10 laptop and desktop, it helps you move, merge, copy, convert, defrag, wipe, hide partition, scan bad sectors and much more. There's free edition for Windows 10/8/7/Vista/XP home computer users. Except 1-Second Rollback technology and bootable media builder, it is the same with paid Professional edition.