University of Oregon

Creating a Partition in Windows


Creating a Partition in Windows 7, Vista, and XP


Creating a separate data partition during installation


During installation of Windows, you will eventually come to a screen that gives you a choice of which partition to install on. On most new computers, there is only one drive: C:. However, we can change these partitions to allow us to install the OS on one drive (in this case meaning one section of the hard disk) and keep our data on another.

  1. Delete any unwanted partitions by selecting them and hitting D. Now hit C to create a partition.
In the new screen, the line “the maximum size...” tells you the amount of unallocated space available. If there are no other partitions, this is also your hard drive size in MB (simply put a decimal before the last three numbers and you have your GB).

  3. Create the windows partition. Most new drives today have hundreds of GB, so you have some wiggle room for extra programs, pagefile and so on. If you've got at least 100 GB, go ahead and give XP 15 GB, Vista 20 and Windows 7 20*. *If you don't have much available, the bare minimum would be more like 10 for XP, 15 for Vista and 16 for Windows 7.

  4. Create the partition that will hold your data. You can use the rest of the space available on the disk if you like, or divide it into segments however you would like.
Proceed with installing Windows on the drive we created for it (usually C:).

  6. Remember to enter the size in MB! Making a 15 GB partition means you must type in 15000.


Creating a separate data partition in an existing copy of Windows

Windows 7 or Vista

If you're running Windows 7 or Windows Vista, luck is on your side.


  1. Right click on My Computer.
Choose Manage > Storage > Disk management. Using this method, we can shrink the size of the existing partition in order to create space for a new one.
Right click on the partition you'd like to make smaller (generally you'll just have the Windows partition). Click Shrink volume; the system will determine if it can be shrunk. Eventually a box will pop up showing the size you can shrink it to and the resulting free space. Adjust it to your specifications and click OK.

  4. Format and name the new partition. You can do this right here in disk manager, or in a normal Windows Explorer window.

  5. Drag and drop your data. You're Done!


Windows XP

Windows XP does not include the handy ability to shrink partitions, but you can mimic the action by using Symantec's PartitionMagic. In PartitionMagic, simply select your drive and use "Resize Partition." Proceed as above.