How do you extend partition with unallocated space in Windows 10

DiskPart is a powerful command-line utility built into Windows that allows you to manage disks and partitions, including extending them—provided there's unallocated space immediately after the target partition.

 How to extend partition in Windows 10 with diskpart

1. Press Win + R, type cmd, then press Ctrl + Shift + Enter.

2. Launch DiskPart:

diskpart

3. List available volumes:

list volume

This displays all volumes (partitions) on your drives. Identify the volume number you want to extend (look at the "Label" and "Size").

3. Select the target volume (Replace X with the number of the volume to extend.):

select volume X

If you want to use all available adjacent unallocated space for extending partition in Windows 10:

extend

Or, specify how much to extend in MB:

extend size=XXXX

Replace XXXX with the number of megabytes (e.g., extend size=10240 for 10GB).

Notes:

If the Extend command fails, it’s likely because the required unallocated space isn't adjacent or the partition isn't NTFS.

DiskPart won't move other partitions to make space. Use a third-party tool in such cases.