How to Partition a Hard Drive on Windows & Mac

You’ve heard about people losing data to a corrupted hard drive sector or, even worse, experiencing a hard drive failure. Hard drives can be fickle, and although many offer a long life of service, you should have a plan for protecting your data. A great way to avoid these troubles is by using multiple hard drive partitions, in conjunction with one of our best online backup providers.

Partitioning is required for drive storage, but it also creates a more secure environment for your data. In this guide on how to partition a hard drive, we’re going to discuss what a partition is and how you can start partitioning on macOS and Windows.

What Is a Partition?

Partitioning is a way of separating your hard drive into multiple sections. A partition can be thought of as a slice of your hard drive. Even though this piece is just a logical separation from your whole drive, the operating system will treat it as an independent drive (this is different from RAID).

Each partition becomes a logical disk, representing a chunk of the physical disk. That allows the operating system — and you — to manage files and data separate from other parts of the drive. Hard drives have to be partitioned and formatted before you can store data on them, but there are many other benefits to having a multi-partition scheme.

Regardless of what OS you’re using, you must set up the partitions and formatting. You can’t write data to a blank drive. The OS needs a volume with a file system to write and store data. The partition is the volume, and formatting creates the file system.

The process varies depending on the OS. Usually, operating systems are set up with multiple partitions, and you can create and format hard disk partitions in several ways. For instance, when installing Windows, one partition will be created for the OS to reside in and another partition will be for recovery.

Reasons to Partition

Partitioning is a solid way to organize your data, which makes finding your files, projects and programs more simple. Separate partitions also make your data easier to backup, saving you from having to sift through multiple folders and directories. You should still use online backup, though, because multiple partitions will not protect you from hard drive failure.

Because partitions are treated as separate drives, you can encrypt them. That means you gain greater control over encrypting a hard drive because you can encrypt on a per-partition basis. Encrypting a whole drive is fine, it’s just that partitioning grants you more options. Read our how to encrypt your hard drive guide for more details on this process.

Partitioning also lets you use multiple operating systems on one hard drive. Having multiple partitions is mandatory for that, as each OS requires its own drive. You’ll also want additional partitions for files and data relative to each OS, as intermingling them will create problems. It improves performance, too.

Speaking to the history of the hard drive, partitioning has been used to make operating systems quicker. The physical structure of a hard drive is such that the outer tracks of the disk offer the highest transfer rates. The first partitions created are situated there and are the fastest, so that’s where you want your OS to live.

While the scope of this guide is limited to basic partitioning, you can do more advanced partitioning with specialized software. For example, if you intend to run a dual boot setup, partition software gives you greater control over your partition management.

How to Partition a Hard Drive in Windows

Partitioning a hard drive in Windows is done through the disk management tool, which is a disk utility included with every version of the OS. The following steps assume the use of Windows 10, but are equally applicable to Windows 7 and 8.1. If you’re unsure of which you have, you can check here. The process doesn’t change much.

Any time you are formatting or partitioning, it’s good to make sure you’ve backed up all your data.

Step 1: Open “disk management.” That can be done via computer management, Cortana or the command prompt. You can also right-click the start button, then select “disk management” from the menu. It looks like this:

Step 2: Once you have disk management open, you may receive an “initialize disk” prompt in a separate window. There, you’ll be asked to specify a partition style. Don’t worry if you don’t see the message, just continue to the next step.

Step 3: Select the hard drive you want to partition at the bottom of the window. It will show as “unallocated.” Right-click it, then select “new simple volume…”

If you don’t see your drive in the drive map, Windows may not recognize it. Double check that it is installed correctly, and restart your PC.

If you’re partitioning an existing drive with data or the OS installed on it, you’ll need to create unallocated space for Windows to work with. Right-click the partition and select “shrink volume…” Windows will tell you how much free space is available to partition and ask you to specify the size of the new one.

Step 4: The new simple volume wizard will appear. Click “next,” then on “specify volume size,” click “next” again, all within the new simple volume wizard window. By default, Windows will create one partition using the maximum amount of unallocated space. If you need a smaller partition, just specify the size in megabytes.

Step 5: Click “next” on “assign drive letter or path.” Windows will automatically assign the first drive letter available, skipping A and B. Drive letter C — i.e., the C drive — is the main hard disk partition that stores the operating system, system files and other applications and files.

Step 6: Next, you can either select “do not format this volume” if you want to format it later, or you can do it now.

Step 7: On the “completing new simple volume” screen, verify your choices and click “finish.” Windows will partition the drive accordingly with the free space, which should only take a minute.

The drive will need to be formatted, unless you did so during step six. After you create a new partition, Windows will try to open the drive and give you a prompt to format it. Follow the steps in our how to wipe a hard drive guide for formatting help.

How to Partition a Hard Drive in macOS

As with Windows, it is a straightforward process if you want to partition on a Mac. Basic partitioning is done using Disk Utility, which is Apple’s built-in disk management tool. Again, make sure your data is backed up before tinkering with your drives.

Step 1: Open Disk Utility. Press the “command” + “space” keys to launch Spotlight, then type “disk utility.” Or:

• Open Finder
• Select “applications”
• Open the “utilities” folder
• Click on Disk Utility to open it

Step 2: Once you’re in the Disk Utility window, select your hard drive on the left side.

Step 3: After you’ve selected your device, click the “partition” tab.

Step 4: Click the “add (+)” button. Then, select the size of your new partition and give it a name.

You can create more partitions by selecting a new partition and clicking the “add (+)” button. That depends on the total amount of free space available, though.

Step 5: Select your desired format for the partition.

Step 6: Click “apply” and macOS will create the new drive partition.

When all that’s done, your new partition should appear as a new volume on the left sidebar of Disk Utility.

Final Thoughts

Hopefully, this guide helped you create a shiny new drive partition that you can use for dual booting or making online backups easier. There is some risk associated with managing your partitions, so plan for all possible contingencies.

The best way to do this is to have a solid backup strategy. Our backup and storage strategy is a good choice.

Having a few partitions is great for mitigating the threat of data loss and streamlining online backups. It can also make restoring data from backups easier, as you know where the data needs to go.

To make sure you’re using the best option for your regular backups, we’ll save you a step and tell you that IDrive is our favorite online backup option, as you can read in our IDrive review. If you have questions about partitioning, or there’s something we left out, comment or tweet at us.