By Cherry / Last Updated September 29, 2021

Why extend partition or volume?

Sometimes, Windows users may find their partition on the basic disk or the volume on the dynamic disk runs out of space quickly and finally suffers from low disk space warning. As a consequence, the computer will run slower gradually and some apps cannot load smoothly as expected. To solve it, you can delete some unnecessary files, uninstall programs, move apps from one drive to another, etc. However, the most effective method should be extending the volume.

How to extend partition with Diskpart?

To extend the partition as you need, you can make use of Diskpart, a native disk management tool of Windows operating system. You can use it to extend an existing volume/partition by following the next steps.

Step1. Open the command-line window by clicking “Start”, typing: “cmd”, or you can press “WIN+R” and type “cmd”. In the command prompt, type ”diskpart”, press Enter to launch Diskpart window.

Step 2. At the Diskpart prompt, type: list disk and press Enter.

Then, all disks will be list at the prompt.

Step 3. Then, type: select disk n and press Enter.

n means disk number. Here, you choose the disk which has the partition you want to extend.

Step 4. Type: list partition and press Enter.

The partition(s) on the selected disk will be listed.

Step 5. Then, you can select the partition which you want to extend. Type: select partition n and press Enter.

n is the partition number you want to extend. Please make sure there is unallocated space behind the partition you want to extend.

Step 6. Type: extend size=n and press Enter.

n is the size in MB you want to add the partition.

Then, it will remind you that Diskpart successfully extended the volume. Here is a screenshot of the details.

Extend Partition

When you’re finished, type exit to end up this progress. If you are extending volumes on a dynamic disk, you can use “volume” to replace “partition”.

★However, Diskpart has the following restrictions when extending partitions:
It can only extend volumes created on dynamic disks, not the volumes created on the basic disk that you have upgraded. If you want to extend a volume on basic disks, you will receive the error” Diskpart failed to extend the volume. Please make sure the volume is valid for extending.”
To extend a basic volume, it must be raw or formatted with NTFS file system.
It can only extend a volume that is followed by an adjacent unallocated space. If not, you may need to delete the neighboring partition.

Partassist.exe command-line: extend partition easily

To evade the limitations of DiskPart, you can turn to AOMEI Partition Assistant Professional. It has the Partassist.exe utility to help resize(extend/shrink) partition without data loss from command prompt. It can extend NTFS and FAT32 partition or volume. Besides, it's able to directly merge non-adjacent unallocated space into the target partition, or allocate free space from one partition to another. Much powerful than DiskPart command line in extending partition in Windows 10, 8, 7. Download the demo version and have a try, please.

Download Free Demo Win 11/10/8.1/8/7/XP
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Install AOMEI Partition Assistant Professional and open it by typing "cd + installation directory of AOMEI Partition Assistant Professional". For example: how to extend partition with Partassist.exe?

First, type: cd C:\Program Files\AOMEI Partition Assistant Professional Edition on 7.2, then, press Enter to open the program.

Next, you should type:partassist.exe /list

Then, it will list the basic situation of all your disk. Then, you can use the command to extend the partition as you want. Like the following screenshot, type: /hd:2 /resize:H /extend:10GB /align, press Enter, it will be executed.

PA Extend Partition

Using AOMEI command line to extend partition, you can follow the other parameters below:

1.partassist.exe /hd:0 /resize:0 /extend:auto /align

or

partassist.exe /resize:F /extend:auto /align

Those two parameters can automatically extend a specified partition using the unallocated space on both sides and align the partition to optimize reading/writing speed.

2.partassist.exe /hd:0 /resize:0 /extend:right

or

partassist.exe /resize:F /extend:right

Those two parameters can automatically extend a specified partition using the unallocated space on its right side.

3. partassist.exe /hd:0 /resize:0 /extend:left /align

or

partassist.exe /resize:F /extend:left /align

Both of them can automatically extend a specified partition using the unallocated space on its left side and align the partition to optimize reading/writing speed.

4. partassist.exe /hd:0 /resize:0 /extend:1000

or

partassist.exe /hd:0 /resize:0 /extend:10GB

Both of them can Extend a specified partition using 1000MB or 10GB unallocated space on its right side.

★Tips:
 "/hd" followed by disk number, which starts with 0.
 "/resize" followed by partition number or drive letter, and the partition number starts with 0. If the specified value is drive letter, disk number can be ignored.
 The value of "/extend" can be left, right, auto or specified size.
 "/align" means align a partition to optimize reading/writing speed. If the beginning of a partition is changed when resizing it (in other words, move the beginning of a partition to a new location, forward or backward), then the "/align" works. But if the beginning of a partition is not changed when resizing it, then the "/align" doesn’t work.
 By default, the specified size is in MB, and GB is also available.

The partassist.exe can help you solve the problem that the Diskpart cannot do. You can use it to manage your disk more flexible.

Easiest way to extend partition with GUI AOMEI Partition Assistant

Not everyone can use CMD well. Employing Diskpart to extend partition is more suitable for people who know it deeply. It cannot be any wrong while operating. Once there is a wrong step, it may cause a big damage. Fortunately, the AOMEI Partition Assistant also has the GUI version, allowing you to extend the partition within a few clicks.

Step1.Launch AOMEI Partition Assistant Professional. It will display its main interface. To extend partition, here you can make use of “Resize Partition”, "Move Partition”, “Merge Partitions”, and“Allocate Free Space”features.

1> If there is unallocated partition adjacent to the partition you want to extend, you can right click the partition, selectResize Partitionto extend the partition with the unallocated space.

Resize Partition

Then, drag the bar towards the right to extend partition with the unallocated space.

Extend System Partition

2> If the unallocated space is not adjacent to the partition you want to extend, you can right click the partition near to the unallocated space, select Move Partition to move the unallocated space to the partition you want to extend. Then, use the Resize Partition to extend the partition.

Move Partition

Then, drag the partition to the left, and it will be moved.

Drag Partition to Left

3> The most effective way is using Merge Partitions to extend the partition. No matter there is unallocated space or not, you can right click the partition you want to extend, select Merge Partitions.

Merge Partitions

Then, you can select the unallocated space or other existing partition to extend the partition you want to extend.

Add Unallocated Space to C Drive

4>If there is no unallocated space, you can use the “Allocate Free Space” feature.

Allocate Free Space

Note: Each operation needs to click "Apply" at the toolbar and then it will be executed.

Summary

Now, you should know how to use Diskpart to extend volume. If it fails because there is no unallocated space near the partition you want to extend, the AOMEI Partition Assistant Professional is a great alternative. If you want to extend partition in Server 2003, 2008, 2012, 2016, or 2019, you can try the AOMEI Partition Assistant Server.