How to add space to C drive in Windows 10/8/7

by Andy, Updated on: February 22, 2021

This article introduces how to add space to C drive in Windows 10/8/7 without formatting or losing data, 3 ways to add more free space to C drive from D or with another disk.

C drive low disk space is common issue in all Windows computers. To solve this problem, nobody likes to reinstall Operating System and all programs. It can't be better if you can add more space to C drive without losing data. To help add free space to C drive in Windows 10/8/7 laptop/desktop, there are two types of tools: Windows native Disk Management and third party partition editor. Because of some shortages, Disk Management can only add space to C drive under specific condition. Partition editor software is much more powerful. In this article, I'll show you detailed steps to add space to C drive in Windows 10/8/7 computer with both tools.

1. How to add space to C drive without any software

Windows 10/8/7 has 2 native tools - Disk Management and diskpart. Diskpart works via command prompt, so it's a bit difficult to common users. Although these 2 native tools work in different way, they have same shortages. Before adding space to C drive with either tool, you must delete the contiguous partition on the right (D: in most of computers).

Although there is Shrink Volume function in Windows 10/8/7 Disk Management, you cannot expand C drive by shrinking D or any other partition. Because Disk Management can only add Unallocated space to the left contiguous partition. Shrink Volume function cannot generate such required Unallocated space, it can only make Unallocated space on the right.

As you see in the screenshot, I got 20GB Unallocated space after shrinking D: drive in my test computer. C drive is nonadjacent and E is on the right, so Extend Volume greyed out for both partitions.

Extend Volume greyed out

Only when you can delete the contiguous D: drive, you can extend C drive without any software. After deleting partition D, you'll get adjacent Unallocated space, then Extend Volume is enabled for C drive.

Do not delete D drive if you installed program in it. If you can delete it, remember to transfer files to other partition in advance.

Steps to add space to C drive in Windows 10/8/7 with Disk Management:

  1. Press Windows and R together on your keyboard, input diskmgmt.msc and press Enter to open Disk Management.
  2. Right click D drive and select Delete Volume.
  3. Right click C drive and select Extend Volume.
  4. Follow pop-up Extend Volume Wizard by clicking Next till Finish.

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

2. How to add space to C drive by shrinking D drive

Obviously, it is not good idea to increase C drive space by deleting other partition. Better than Disk Management, third party software can make Unallocated space on the left while shrinking partition, so C drive can be extended easily. In this way, Operating System, programs and associated settings, and anything else keep the same with before.

There are many software in the market, but you'd better make a backup and run the safest one, because there's potential system damage and data loss risk while resizing partitions. Better than other software, NIUBI Partition Editor has advanced 1-Second Rollback, Virtual Mode and Cancel-at-well technologies to protect system and data.

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

Main window

Steps to add space to C drive in Windows 10/8/7 from contiguous D drive :

Right click D: drive and select "Resize/Move Volume". In the pop-up window, drag left border towards right, or enter an amount in the box of "Unallocated space before". (1GB=1024MB)

Shrink D

Then this partition is shrunk and Unallocated space is made on the left side.

NIUBI Partition Editor

Right click C: drive and select "Resize/Move Volume" again, drag right border towards right in the pop-up window.

Extend C drive

Then 20GB Unallocated space is added to C drive.

Extend volume C

Click Apply on top left to confirm and execute. (Real disk partition won't be changed before this step.)

3. How to add free space to C drive from nonadjacent partition

In some computers, there's not plenty of free space in the adjacent partition (D:), then you can add free space to C: drive from any non-adjacent partition on the same disk.

Steps to add more space to C drive in Windows 10/8/7 from non adjacent partition:

  1. Follow step 1 above to shrink the nonadjacent partition (E:) and make Unallocated space on the left.
  2. Right click partition D: and select "Resize/Move Volume", drag middle position towards right in the pop-up window, then Unallocated space will be moved behind C drive.
  3. Follow step 2 to merge Unallocated space to C drive.

Video guide to add space to C: drive from D or E in Windows 10/8/7:

Video guide

4. How to add more space to C drive with another disk

In some computers, there's no other partition or not enough free space on the same disk. In that case, no software can add space to C drive from a separate disk, because the size of a physical disk is fixed. However, there are still 2 ways to add disk space to C drive in Windows 10/8/7 with NIUBI Partition Editor.

  1. Move a data volume to another disk, delete it and add its disk space to C drive.
  2. Copy system disk a larger one and extend C drive with extra disk space.

Besides shrinking partition and adding space to C drive in Windows 10/8/7/Vista/XP, NIUBI Partition Editor helps do many other disk management operations.

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