Extend a volume in Windows Server with diskpart

This article describes how to extend a volume in Windows Server® 2008 R2, 2012 R2,
and 2016 with diskpart. It also explains the difference between extending and shrinking
or partitioning a volume.


Extending a volume increases the size of an already existing partition. You can do this only if
unallocated space is available.

To extend a volume, you can either use the built-in disk management tool or the command-line
tool diskpart. Keep in mind that you need administrator permissions to perform these tasks.

Extending by using diskpart

To extend a volume by using the diskpart command-line tool, use the following steps. The code uses
the C:\ drive (disk 0) as an example.

  1. To open the command-line prompt, click the Start button and type cmd.

  2. To start the diskpart utility, type diskpart.

  3. To view the current disk information, enter list disk.

  4. To select the disk you want to extend, enter select disk 0.

  5. To view the volume information, enter list vol.

  6. To select the desired volume, enter select vol 0.

  7. To extend the volume to the maximum available size, enter extend.

    You can specify the amount of space to add to the volume in megabytes by typing
    extend size=1000, which adds 1000 MB to the existing volume.

  8. To verify the new volume size, enter list vol.