How to Partition a Hard Drive

Hard drives must be partitioned before being formatted in Windows

What to Know

  • The first thing to do after installing a hard drive is to partition it.
  • To partition a drive, open Disk Management, select the drive, create a volume at the size you want, and select a drive letter.
  • You'll want to format the drive next unless you have advanced plans for the partition but that's not very common.

To partition a hard drive in Windows means to section off a part of it and make that part available to the operating system.

In other words, a hard drive isn't useful to your operating system until it's partitioned. Additionally, it's not available to you to store files on until you format it (which is another, just as simple process).

Most of the time, this "part" of the hard drive is the entire usable space, but creating multiple partitions on a hard drive is also possible so that you can store backup files in one partition, movies in another, etc.

Manually partitioning (as well as formatting) a hard drive is not necessary if your end goal is to install Windows onto the drive. Both of those processes are included as part of the installation procedure, meaning you don't need to prepare the drive yourself. See How to Clean Install Windows for more help.

How to Partition a Hard Drive in Windows

Don't worry if this process sounds a bit more complicated than you thought because it's not. Partitioning a hard drive in Windows isn't at all hard and usually only takes a few minutes to do.

Here's how to do it:

These instructions apply to Windows 10, Windows 8, Windows 7, Windows Vista, and Windows XP.

  1. Open Disk Management, the tool included in all versions of Windows that lets you partition drives, among a number of other things.

    Disk Management section in Computer Management window

    In Windows 10 and Windows 8/8.1, the Power User Menu is the easiest way to start Disk Management. You can also start Disk Management via command-line in any version of Windows, but the Computer Management method is probably best for most people.

    See What Version of Windows Do I Have? if you're not sure.

  2. When Disk Management opens, you should see an Initialize Disk window with the message "You must initialize a disk before Logical Disk Manager can access it."

    Ok button in Initialize Disk dialog

    In Windows XP, you'll see an Initialize and Convert Disk Wizard screen instead. Follow that wizard, making sure to not select the option to "convert" the disk, unless you're sure you need to. Skip to Step 4 when done.

    Don't worry if this window doesn't appear. There are legitimate reasons you may not see it—we'll know soon if there's a problem or not. Skip down to Step 4 if you don't see this.

  3. On this screen, you're asked to choose a partition style for the new hard drive. Choose GPT if the new hard drive you installed is 2 TB or larger. Choose MBR if it's smaller than 2 TB.

    Choose OK after making your selection.

  4. Locate the hard drive you want to partition from the drive map at the bottom of the Disk Management window.

    You might need to maximize the Disk Management or Computer Management window to see all the drives on the bottom. An unpartitioned drive will not show up in the drive list at the top of the window.

    If the hard drive is new, it will probably be on a dedicated row labeled Disk 1 (or 2, etc.) and will say Unallocated. If the space you want to partition is part of an existing drive, you'll see Unallocated next to existing partitions on that drive.

    If you don't see the drive you want to partition, you may have installed it incorrectly. Turn off your computer and double-check that the hard drive is properly installed.

  5. Once you've found the space you want to partition, tap-and-hold or right-click anywhere on it, and choose New Simple Volume.

    New Simple Volume right-click menu in Disk Management

    In Windows XP, the option is called New Partition.

  6. Choose Next > on the New Simple Volume Wizard window that appeared.

    Next button in New Simple Volume Wizard

    In Windows XP, a Select Partition Type screen appears next, where you should choose Primary partition. The Extended partition option is useful only if you're creating five or more partitions on a single physical hard drive. Select Next > after making the selection.

  7. Choose Next > on the Specify Volume Size step to confirm the size of the drive you're creating.

    Next button on Specify Volume Size dialog

    The default size that you see in the Simple volume size in MB: field should equal the amount shown in the Maximum disk space in MB: field. This means that you're creating a partition that equals the total available space on the physical hard drive.

    You're welcome to create multiple partitions, that will eventually become multiple, independent drives in Windows. To do so, calculate how many and how large you want those drives to be and repeat these steps to create those partitions. For example, if the drive is 61437 MB and you want to partitions, specify an initial size of 30718 to partition only half the drive, and then repeat the partitioning again for the rest of the Unallocated space.

  8. Select Next > on the Assign Drive Letter or Path step, assuming the default drive letter you see is OK with you.

    Next button on the Assign Drive Letter or Path dialog

    Windows automatically assigns the first available drive letter, skipping A & B, which on most computers will be D or E. You're welcome to set the Assign the following drive letter option to anything that's available.

    You're also welcome to change the letter assigned to this hard drive later on if you want. See How to Change Drive Letters in Windows for help doing that.

  9. Choose Do not format this volume on the Format Partition step, and then select Next >.

    Do not format this volume radio button and Next button in Format Partition dialog

    If you know what you're doing, feel free to format the drive as part of this process. However, since this tutorial focuses on partitioning a hard drive in Windows, we've left the formatting to another tutorial, linked in the last step below.

  10. Verify your choices on the Completing the New Simple Volume Wizard screen, which should look something like this:

    New Simple Volume Wizard screen showing new drive specifications
    • Volume Type: Simple Volume
    • Disk selected: Disk 1
    • Volume size: 61437 MB
    • Drive letter or path: F:
    • File system: None
    • Allocation unit size: Default

    Because your computer and hard drive are unlikely exactly like mine, expect your Disk selected, Volume size, and Drive letter or path values to be different than what you see here. File system: None just means that you've decided not to also format the drive right now.

  11. Choose Finish and Windows will partition the drive, a process that will only take a few seconds on most computers.

    You might notice that your cursor is busy during this time. Once you see the new drive letter (F: in our example) appear in the listing at the top of Disk Management, then you know the partitioning process is complete.

  12. Next, Windows will try to open the new drive automatically. However, since it's not yet formatted and can't be used, you'll see this message instead: "You need to format the disk in drive F: before you can use it. Do you want to format it?"

    This only happens in Windows 10, Windows 8, and Windows 7. You won't see this in Windows Vista or Windows XP and that's perfectly fine. Just skip to the last step below if you're using one of those versions of Windows.

  13. Select Cancel and then proceed to Step 14 below.

    Cancel button on formatting dialog in Disk Management screen

    If you're familiar with the concepts involved with formatting a hard drive, feel free to choose Format disk instead. You can use our tutorial linked in the next step as a general guide if you need to.

  14. Continue to our How to Format a Hard Drive in Windows tutorial for instructions on formatting this partitioned drive so you can use it.

Advanced Partitioning

Windows doesn't allow for anything but very basic partition management after you create one, but a number of software programs exist that can help if you need them.

See our Free Disk Partition Management Software for Windows list for updated reviews on these tools and more information on what exactly you can do with them.