3 Ways to Extend C Drive in Windows 10/8/7 with Free Tools

by John, Updated on: September 24, 2026

More and more Windows 10 computers use an SSD for the system disk. This is useful for improving computer performance, because the read and write speeds of an SSD are much faster. But on the other hand, an SSD is more expensive, so it is usually smaller than a traditional mechanical hard disk. Therefore, the C drive is more likely to run out of space. When this happens, nobody likes to reinstall the Operating System and all their programs. Many people ask whether it is possible to extend the C drive in a Windows 10 computer without losing data. The answer is yes. This article introduces how to extend the C drive for a Windows 10 laptop/desktop/tablet with free partition tools.

Extend C drive

Extend the C Drive in Windows 10 Disk Management Without Any Software

To help extend the C drive in Windows 10/8/7, there are 2 native tools: Disk Management and Diskpart. Diskpart is a command-line tool, so it is not good for every user. Disk Management is easier to use with a graphic interface. Although these native tools work in different ways, they have the same shortages when resizing a partition in Windows 10.

To extend the C drive in Windows 10/8/7 using Diskpart or Disk Management, your disk partition configuration must meet these requirements:

  1. There is an adjacent partition (such as D:) on the right of the C drive.
  2. There are no programs installed in the D drive, so you can delete it.
  3. There is a third partition to save all files from drive D.
  4. If your system disk is MBR, the adjacent D drive must be a Primary partition.

There is another "Shrink Volume" function; why not shrink D to expand the C drive? Because to expand a partition with either Windows native tool, there must be adjacent unallocated space on the right. You cannot get such required unallocated space by shrinking other partitions with either native tool. As seen in the screenshot, the unallocated space shrunk from D is non-adjacent to the C drive; therefore, "Extend Volume" is grayed out.

Extend Volume greyed out

If you want to increase C drive space for a Windows 10 computer without any software, you must delete D to get contiguous unallocated space.

Note:

  • Do not delete D if you installed programs in it.
  • The D drive in this article refers to the contiguous partition on the right of the C drive. In some computers, it is E.

Steps to extend the C drive in Windows 10 via the Disk Management tool:

  1. Back up or transfer all files in the adjacent D: drive.
  2. Press the Windows + X keys together and click Disk Management in the list.
  3. Right-click D: and select "Delete Volume"; its space will be changed to "unallocated".
  4. Right-click the C: drive and select "Extend Volume".
  5. Simply click the "Next" button until "Finish" in the pop-up "Extend Volume Wizard" window, and then the C drive will be extended in a short time.

Extend the C Drive in Windows 10 with Free Partition Software

Obviously, it is not a good idea to extend the C drive by deleting another partition. If there is no other partition to transfer files to, or if the D drive is Logical, you cannot extend the C drive even after deleting D. With NIUBI Partition Editor, you can shrink the D drive and create unallocated space on the left; then the C drive can be extended easily. There is a free edition for Windows 11/10/8/7/Vista/XP home computer users. Besides shrinking and extending partitions, this free tool helps you perform operations such as moving, merging, converting, defragging, hiding, and wiping partitions.

There are several ways to expand the C: drive on a Windows 10/8/7/Vista/XP computer. Select the corresponding method according to your own disk partition configuration.

1. Increase C Drive Space by Shrinking D or E

In most cases, there is another volume on the same disk, whether it is contiguous or non-adjacent to the C drive. You just need to shrink this volume to get unallocated space and then add it to the C drive. After extending the C drive for your Windows 10 computer, your Operating System, programs, and everything else will remain exactly the same as before. To extend the C drive on a Windows 10/8/7/Vista/XP computer, you just need to click, drag, and drop on the disk map.

Download NIUBI Partition Editor, and you will see the main window with your disk partition structure and other information. Available operations are listed on the left and by right-clicking.

NIUBI Partition Editor

Steps to extend the C drive in Windows 10/8/7 without losing data:

  1. Right-click the D: drive and select "Resize/Move Volume"; drag the left border to the right in the pop-up window. Then the D: drive will be shrunk, and unallocated space will be created on the left side.
    Shrink D
  2. Right-click the C: drive and select "Resize/Move Volume" again; drag the right border to the right to merge this unallocated space. Then the C: drive will be extended.
    Extend C drive
  3. Click the "Apply" button on the top left to execute.

If you want to get free space from a non-adjacent partition, there is an additional step to move the unallocated space to the left before adding it to the C drive.

How to extend the C: drive in Windows 10 with other partitions on the same disk:

Video guide

2. Extend the C Drive Partition with Another Disk

In some computers, there is no available free space on the same disk. For example, there is no other volume or the whole system disk is full. In that case, no software can extend the C drive by adding space from another separate disk. A separate disk means Disk 0, 1, etc., as shown by NIUBI Partition Editor.

To enlarge the C drive in a Windows 10/8/7/Vista/XP computer under this condition, you have 2 options:

  1. Move a data volume to another disk, delete it to get unallocated space, and then add it to the C drive.
  2. Copy the whole disk to a larger one and extend the C drive with the extra disk space.

If you use any type of hardware RAID, do not break the RAID array or perform any operations on the RAID controller; simply follow the same steps above.

In Summary

When you need to extend the C drive on a Windows 10/8/7/Vista/XP computer, Windows native tools can only accomplish this by deleting the contiguous primary partition. As a professional disk partition tool, NIUBI Partition Editor provides a full solution to extend the C drive without losing data. Compared with other tools, it features Virtual Mode, Cancel-at-Will, 1-Second Rollback, and Hot Clone technologies to protect your system and data. Besides shrinking and extending partitions, it helps you perform many other operations such as moving, copying, converting, merging, wiping, hiding partitions, scanning for bad sectors, optimizing file systems, and much more.

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