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3 Ways: How to Increase C Drive Space in Windows 11/10/8/7

Updated by Roxanne on Dec 13, 2021
Written by Jean
mins read

This page introduces how to increase C drive space in Windows 11/10/8/7 so as to extend C drive, speed up PC, and optimize your computer's performance.

On this page, you'll learn:

  1. 1. Why need to increase C drive?
  2. 2. What is the best tool for extending C drive?
  3. 3. How to increase C drive space in Windows 11/10/8/7 for free?

Let's see how to enlarge your system C drive on your computers now.

Why Need to Increase C Drive Space

Accordingly, the reasons why people need to increase the C drive space are various. Mostly, it could be divided into the following two cases:

#1. C drive full, Windows warns with "Low Disk Space" message

One day, you may find the system partition (C: drive) does not have much free disk space left, and the Windows OS pops up a low disk space warning message, which states as: "You are running out of disk space on Local Disk (C:)..."

low disk space warning tells you to increase c drive space

#2. Windows slows down, computer performances goes down

As time goes by, Windows OS, installed applications and programs will generate some application data, cache files, which will take up huge space on your C drive. So it is to your personal user data.

With the C drive getting full, the running speed of Windows OS and the performance of your computer will go down. Problems like high CPU usage, high ram memory, Windows 11/10 update stuck, etc., come along.

If you are with one of the listed cases, the best resolution is to increase the C drive space on your computer. How to do it? You'll need a reliable disk partitioning tool that allows you to extend local disk C: drive. 

3 Best Tools for Extending C Drive in Windows 11/10/8/7

In this part, we'd like to introduce 3 best disk management tools to you and you can pick up one of them to extend your system C drive in Windows 11/10/8/7 for free:

  1. #1. Third-party EaseUS Partition Master
  2. #2. Windows Disk Management
  3. #3. DiskPart CMD

Here is a comparison table that will help you to decide which tool suit your need the most in increasing C drive space:

Comparison EaseUS Partition Master Windows Disk Management DiskPart CMD
Increase C drive with adjacent unallocated space
Extend C drive space with non-adjacent unallocated space × ×
Best for All levels of Windows users, beginners' best choice Experienced Windows users Administrators

Note that if you prefer an easier solution, apply EaseUS EaseUS Partition Master Free - Partition Master to increase C drive space in Windows 11/10/8/7/XP/Vista with success.

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Pick up one of the free methods and follow the respective tutorial as shown below to start extending your local disk C drive now. These methods also work to extend data volumes on your PC. 

Method 1. How to Increase C Drive Space with EaseUS Partition Master

Applies to: Increase C drive space, extend system partition in a few simple clicks, no data loss. 

EaseUS partition manager software is designed for all levels of Windows users with a simple and intuitive interface. It supports to free manage partitions, including increasing C drive space, shrinking or extending partitions, merging non-adjacent partitions, etc.

Video Tutorial: Increase C Drive and Manage Hard Drive Partition in Windows

Step-by-step Guide: Enlarge C Drive Space in Windows 11/10/8/7

If there is unallocated space on your system disk, you may got to Step 2 and start by right-clicking C drive and select "Resize/Move":

Step 1: Free up unallocated space for C drive.

If there is no unallocated space on the system disk, right-click on a partition next to the C: drive and select "Resize/Move".
Drag left panel of the partition to shrink and leave unallocated space behind the system C: drive and click "OK".

Step 2: Increase C drive space.

1. Right-click on C: drive and select "Resize/Move".

Extend System partition

2. Drag the system partition end into unallocated space so to add space to C: drive.

Add space to C drive

Step 3: Keep all changes to extend C: drive

Click the "Execute Operation" and click "Apply" to keep all changes so to extend the system C: drive.

Confirm to extend system C drive

Method 2. How to Increase Space in C Drive with Windows Disk Management

Applies to: Extend C drive with manual operations, some operations may cause data loss. 

Disk Management is a Windows built-in tool that supports to increase partition size with its "Extend Volume" feature. However, the program has some limitations in increasing disk space:

  • Extend Volume only works on NTFS and RAW partition. FAT32 and other file systems are not supported.
  • The Extend Volume will grey out if there is no adjacent unallocated space behind the target partition.

So, the ways to increasing C drive with or without adjacent unallocated space are different. Open the Disk Management, and follow the right tutorials listed below to extend the local disk C drive on your own now:

#1. Increase C Drive Space with Adjacent Unallocated Space

Step 1. Right-click This PC/My Computer, click "Manage", select "Disk Management" under Storage.

Step 2. Locate and right-click on the local disk C drive, and choose "Extend Volume".

extend c drive with disk management

Step 3. Set and add more space to your system C drive and click "Next" to continue. 

Step 4. Click "Finish" to complete the process.

Note that if that unallocated space on your system disk is not behind the C drive, you can't extend C drive in Disk Management. In this case, you can turn to EaseUS Partition Master with tutorials as shown in Method 1 for help.

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#2. Extend C Drive without Unallocated Space or No Continuous Unallocated Space

Step 1. Right-click on This PC/My Computer, select "Manage" > "Disk Management".

Step 2. Right-click the adjacent partition next to the C drive (it would be D drive by default), choose "Shrink Volume".

Step 3. Enter the amount of space to shrink, click "Shrink" to confirm.

Shrink volume

Step 4. Right-click on local disk C drive and select "Extend Volume". 

Step 5. Follow the on-screen instructions to add more space to the system C drive.

Method 3. How to Extend C Drive Space with DiskPart CMD Commands

Applies to: Extend C drive space with command lines, false operation may cause serious problems.

The third free method to extend system partition space is to run CMD command using DiskPart. It's an administrator tool that might be a bit complex for normal Windows users. Therefore, you should be very careful with this process.

#1. Extend C drive with Contiguous Unallocated Space 

Step 1. Open Diskpart prompt window

  • Press Windows + R keys to open the Run dialog, type cmd and hit Enter to open Command Prompt as Administrator.
  • Type diskpart and hit Enter to open DiskPart.

Step 2. Type CMD command lines and hit Enter each time to extend C drive

  • list disk
  • select disk x (Replace X with the disk number of your system disk.)
  • list volume
  • select volume x (Replace X with the partition number of your C drive.)
  • extend size =number (Normally, the default size unit is MB.)
  • exit

After this, you can restart PC and you'll get a larger C drive on your computer.

#2. Extend C Drive When There Is No Unallocated Space Behind

If there is no adjacent unallocated space behind your system C drive, you'll encounter this error as shown below:

"Virtual Disk Service error: There is not enough usable space for this operation".

Can't extend c drive as there is no adjancent unallocated space next to C drive

In this case, you have two options: 1. Revert to Method 1 and extend C drive space using EaseUS Partition Master; 2. Delete the adjacent drive behind C drive to get an unallocated space.

If you prefer the 2nd option, remember to back up all useful data to another location first. Now, follow the steps below to extend C drive for free:

Step 1. Open Diskpart prompt window

  • Open the Run dialog, type cmd and hit Enter to open Command Prompt as Administrator.
  • Type diskpart and hit Enter to open DiskPart.

Step 2. Type command lines below and hit Enter each time:

  • list disk
  • select disk x (Replace X with the disk number of your system disk.)
  • list volume
  • select volume * (Replace * with the partition number that you want to delete.)
  • delete volume
  • select volume x (Replace X with the disk number of your C drive.)
  • extend size =number (Normally, the default size unit is MB.)
  • exit

After this, you can restart PC to keep all the changes, later, you'll see that your C drive is larger and the computer is running faster than before.

Bonus Tips for Increasing C Drive Space

Besides the above-presented methods, here we also have some bonus tips that can help you fix the C drive low space issue and optimize computer performance. 

Follow the tips below to get an even larger C drive and a faster computer:

1. Back-Up Big Data to An External Storage Device

If you have a certain number of big files saved on your C drive but you don't need to use them frequently, we suggest you back up those files to an external storage device.

You may apply reliable Windows file backup software for help. 

2. Delete Useless Large Files in C Drive Regularly

Deleting the old or unnecessary files on system drive will free up space to ensure the normal operations of the Windows system. Follow to see how to locate and delete large files in Windows 10/8/7.

3. If Extend Volume Greyed Out, Turn to EaseUS Partition Master

When you can't extend a volume using Disk Management, it's highly possible that there is no unallocated space behind your target volume. And EaseUS Partition Master can resolve this issue effectively with its Resize/Move feature. You can also apply this tool to partition the hard drive.

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Sum Up

On this page, we explained why do people need to increase C drive space and introduced the 3 best disk management tools for Windows 10/8/7 users to extend the system C drive and other partitions.

If you are a Windows server user, you may also refer to the listed methods as shown above to enlarge a hard drive partition. 

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About the Author

Updated by Roxanne

Roxanne is one of the main contributors to EaseUS and has created multiple posts on digital devices like PCs, Mobile phones, tablets, Mac, etc. She loves to share ideas with people of the same interest.

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Written by Jean

Author Jean has been writing tech articles since she was graduated from university. She has been part of the EaseUS team for over 5 years. Her special focuses are data recovery, disk partitioning, data space optimization, data backup and Mac OS. By the way, she's an aviation fan!

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