How to Partition a Hard Drive on Windows 11

To partition a hard drive in Windows 11, open Disk Management, right-click the drive, and choose Shrink Volume to free up space. Then right-click the new Unallocated space, choose New Simple Volume, and follow the wizard.

Back up your files first. Shrinking a volume normally keeps your files, but it’s always safer to have a copy. These steps follow Microsoft’s Disk Management guide.

In this guide:

• Shrink a drive to make room
• Create the new partition
• Create a D drive
• If you can’t shrink as much as you want
• Use diskpart instead
• Partition a new second drive
• Undo a partition later
• FAQs

Step 1: Shrink a Drive to Make Room

1. Right-click the Start button and click Disk Management. See other ways to open Disk Management.
2. Right-click the drive you want to split, such as C:, and choose Shrink Volume. For C:-specific limits and the diskpart method, see how to split the C drive in Windows 11.
3. Enter how much space to free up, in megabytes (MB). 1,024 MB equals 1 GB.
4. Click Shrink. The freed space shows up as Unallocated.

Microsoft notes that Windows moves your files automatically when shrinking, so you don’t need to reformat. These steps use a basic NTFS volume, such as the normal Windows C: drive. Use an administrator account to manage it.

Result: Disk Management shows a black bar labeled Unallocated next to the drive you shrank. Your files stay on the original volume.

Step 2: Create the New Partition

1. Right-click the Unallocated space and choose New Simple Volume.
2. Click Next.
3. Enter the size of the new partition, or keep the maximum, and click Next.
4. Pick a drive letter, such as D: if it is available, and click Next.
5. Keep the default format settings (NTFS works for most people), type a name in Volume label if you want, and click Next.
6. Click Finish.

If you would rather format later, choose Do not format this volume on the Format Partition screen. Otherwise, the default settings are fine for most people.

Result: The new partition gets its own drive letter and appears in File Explorer, ready for files.

How to Create a D Drive Specifically

Follow the shrink and New Simple Volume steps above, then select D on the wizard’s drive-letter screen. Format only the new volume you are creating from unallocated space. Do not format or delete an existing volume to make its letter available.

If D is not offered in the list, choose another available letter. Check Disk Management to see what already uses D before considering any letter changes. A separate partition on the same disk organizes files; it does not add physical storage or protect your files if that disk fails.

If you already have a healthy data volume that just needs a letter, you do not need to shrink C or create another partition. Follow Microsoft’s drive-letter instructions instead. Do not change the letter of a volume containing Windows or installed apps: apps can stop working after a letter change.

The new drive shows up in File Explorer under This PC.

Why Can’t I Shrink the Drive as Much as I Want?

Some files, like the paging file and shadow copies, can’t be moved. Microsoft says you can’t shrink a drive past the point where those files sit. To free more space, you’d need to move or turn off those files first, which is an advanced step.

If the shrink fails or stops early, Microsoft suggests checking the Application log in Event Viewer for event ID 259, which names the unmovable file. The paging file is a common culprit; you can temporarily move it to another disk in the virtual memory settings, shrink the drive, then move it back. A disk with too many bad clusters can’t be shrunk at all.

Result: You know why the available shrink size is smaller than your free space, and how to free more if you need it.

How to Partition a Drive With Diskpart

If you prefer the command line, Microsoft documents a diskpart method for the shrink step.

1. Open Command Prompt as an administrator and type diskpart.
2. Type list volume and note the number of the volume you want to shrink.
3. Type select volume followed by that number.
4. Type shrink desired= followed by the amount in MB, such as shrink desired=51200 for 50 GB.

Then go back to Disk Management and use New Simple Volume on the unallocated space, as shown above. If you leave out the size, diskpart reclaims as much space as it can.

Partitioning a New Second Drive

A brand-new internal drive may show up in Disk Management as Not Initialized. Right-click the disk, choose Initialize Disk, and pick a partition style. Microsoft recommends GPT for modern UEFI computers and large drives, and MBR only for older hardware. If the disk shows as Offline, right-click it and choose Online first.

The whole drive then appears as unallocated space, so you can skip the shrink step and go straight to New Simple Volume. Repeat it with a smaller size each time if you want several partitions.

How to Undo a Partition Later

To merge the space back, back up the new partition, right-click it, and choose Delete Volume. Then right-click the original drive and choose Extend Volume. Per Microsoft’s extend guide, this only works when the unallocated space sits directly after that volume on the same disk, and the volume uses NTFS or ReFS. See how to extend the C drive in Windows 11 for details.

Frequently Asked Questions

Why should you partition a hard drive?

A separate partition can keep your personal files apart from Windows, give you room to install another operating system, or organize large collections of files. If you only want to test another system, a virtual machine may be easier.

Will partitioning erase my files?

Shrinking doesn’t. Microsoft says ordinary files are moved automatically, with no reformat needed. Formatting or deleting a volume does erase it, so only format the new partition.

Can I format the partition that has Windows on it?

No. Windows can’t format a disk or partition that is in use, including the one it runs from.

How do I delete a partition?

In Disk Management, right-click the partition and choose Delete Volume. This erases everything on it, so back it up first.

Should I make a recovery drive first?

It’s a good idea before making disk changes. Here is how to make a Windows 11 recovery USB.

To see which file system a drive or USB stick uses, see how to check the file format of a USB flash drive.