How To Partition a Hard Drive

Hard Drives Must be Partitioned Before Being Formatted in Windows

Screenshot of the New Simple Volume Wizard in Windows 10
Simple Volume Wizard (Windows 10).

The first thing to do after installing a hard drive is to partition it. You have to partition a hard drive, and then format it, before you can use it to store data.

To partition a hard drive in Windows means to section off a part of it and make that part available to the operating system. Most of the time, the "part" of the hard drive is the entire usable space, but creating multiple partitions on a hard drive is also possible.

Don't worry if this sounds like more than you thought - partitioning a hard drive in Windows isn't hard and usually only takes a few minutes to do.

Follow the easy steps below to partition a hard drive in Windows 10, Windows 8, Windows 7, Windows Vista, or Windows XP:

Note: 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

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

    Note: 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 which version of Windows you have.
  1. 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."

    Tip: 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 on to Step 4 if you don't see this.

    Note: In Windows XP, you'll see an Initialize an 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.
  1. 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. Tap or click OK after making your selection.
  2. Locate the hard drive you want to partition from the drive map at the bottom of the Disk Management window.

    Tip: You may 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.

    Note: 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.

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

    In Windows XP, the option is called New Partition....
  4. Tap or click Next > on the New Simple Volume Wizard window that appeared.

    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. Click Next > after making the selection.
  1. Tap or click Next > on the Specify Volume Size step to confirm the size of the drive you're creating.

    Note: 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.

    Tip: 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.
  2. Tap or click Next > on the Assign Drive Letter or Path step, assuming the default drive letter you see is OK with you.

    Note: 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.

    Tip: 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.
  3. Choose Do not format this volume on the Format Partition step and then tap or click Next >

    Note: 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, I've left the formatting to another tutorial, linked in the last step below.
  4. Verify your choices on the Completing the New Simple Volume Wizard screen, which should look something like this:
    • Volume Type: Simple Volume
    • Disk selected: Disk 1
    • Volume size: 10206 MB
    • Drive letter or path: D:
    • File system: None
    • Allocation unit size: Default
    Note: 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 that what you see here. File system: None just means that you've decided not to also format the drive right now.
  5. Tap or click on the Finish button and Windows will partition the drive, a process that will only take a few seconds on most computers.

    Note: You may notice that your cursor is busy during this time. Once you see the new drive letter (D: in my example) appear in the listing at the top of Disk Management, then you know the partitioning process is complete.
  6. Next, Windows tries to open the new drive. However, since it's not yet formatted and can't be used, you'll see a "You need to format the disk in drive D: before you can use it. Do you want to format it?" instead.

    Note: 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 Step 14 if you're using one of those versions of Windows.
  7. Tap or click Cancel and then proceed to Step 14 below.

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

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