How to Adjust/Resize C Drive in Windows 10/11 Computer

by Lance, Updated on: May 18, 2022

C drive is allocated while installing Windows Operating System or by desktop/laptop manufacturer, sometimes you need to resize C drive if it is too large or small. For example, C drive is very large in some computers, so users want to decrease it to create more partitions. In some computers, C drive is getting full, so users want to increase free space and expand it. Unlike data partitions, C drive is where Operating System located, so you'd better pay more attention. In this article, I'll introduce how to resize C drive in Windows 10/11 without losing data. Adjust C drive size with Windows native Disk Management and safe partition software.

Resize C drive in Windows10/11 without software

The same with previous Windows 7/8, Windows 10/11 has native Disk Management utility to help change partition size without losing data. The built-in "Shrink Volume" function can decrease partition size to make Unallocated space. "Extend Volume" can increase partition size with adjacent Unallocated space on the right side. However, if you want to extend a partition by shrinking another one, Disk Management cannot help you.

1. How to resize C drive to smaller size

It is easy to resize C drive and data partition with Disk Management tool, but you may encounter issue while shrinking C drive with this tool, for example:

Steps to resize C drive smaller in Windows 10/11 Disk Management:

  1. Press Windows + X keys together, or press Windows + R together and then input diskmgmt.msc to open Disk Management.
  2. Right click C drive and select Shrink Volume.
  3. Click Shrink to use default maximum space, or enter an amount in MB (1024MB=1GB) manually.

In most of computers, C drive is formatted with NTFS. If your C drive is FAT32, Shrink Volume will be grayed out.

Shrink C drive

2. How to resize C volume to larger size

With Disk Management, you can only enlarge C drive by deleting D (the contiguous partition on the right side). Why not shrinking D to expand C drive? Because Extend Volume function only works when there's contiguous Unallocated space on the right. Unallocated space that shrunk from D (or any other partition) is nonadjacent to C drive, so Extend Volume is grayed out for C drive.

Extend Volume greyed

Do not delete D if you installed programs in it, otherwise, you have to reinstall all programs.

Steps to resize C drive larger in Windows 10/11 without software:

  1. Migrate all files in D: drive to other place.
  2. Right click D: in Disk Management and select Delete Volume.
  3. Right click C drive and select Extend Volume.
  4. Simply click Next in next dialog boxes.
  5. Click Finish to confirm and execute.

If D is a Logical drive, you still cannot extend C drive in Disk Management after deleting D.

Best way to resize partition C in Windows 10/11

With third party software, you can extend C drive without deleting any partitions, Operating System, programs and anything else keep the same with before. However, you'd better make backup in advance and run safe partitioning software, because there is potential data loss and system damage risk. As the safest tool, NIUBI Partition Editor is recommended by many editors, because it has many advantages:

Comparing with Windows Disk Management:

  • Both NTFS and FAT16/32 partitions are supported.
  • Make Unallocated space on either side when shrinking a drive.
  • Extend partition with adjacent Unallocated space on either side.
  • Move and merge Unallocated space to nonadjacent partition.
  • Much easier, you just need to drag and drop on the disk map.

Comparing with other partitioning software:

To change C drive size in Windows 11/10/8/7/Vista/XP home computer, NIUBI has free edition to help you. Download this tool and you'll see initial disk partition size and structure on the right.

Main window

How to resize C drive volume in Windows 11/10/8/7/Vista/XP with NIUBI:

Step 1: Right click drive D and select "Resize/Move Volume", drag left border towards right in the pop-up window.

Shrink D

Drive D is shrunk and Unallocated space is made on its left side.

Shrink D rightwards

Step 2: Right click drive C and select "Resize/Move Volume" again, drag right border towards right to combine the Unallocated space.

Extend C drive

As you see, C drive is resized from 30GB to 50GB.

Extend volume C

Remember to click Apply on top left to execute, otherwise, real disk partitions won't be modified.

Follow the steps if you want to shrink C drive in Windows 10/11 to extend system reserved partition or increase D drive space.

Adjust C drive partition size with another disk

If there is not enough free space in contiguous D drive, you can shrink other non-adjacent partitions on the same disk, then you just need an additional step to move Unallocated space next to C drive.

But if there is no other data volume on the same disk, no partitioning software can extend C drive with free space on another separate disk. In this case, you can clone this disk to a larger one and adjust partition size with extra disk space. If there's other partition on the same disk, you may also consider move partition to another disk, then delete this partition and add its space to C drive.

Besides resizing partitions without losing data, NIUBI Partition Editor helps you do many other operations such as merge, copy, move, convert, defrag, wipe, hide partition, scan bad sectors, etc.