How to Partition Your Mac's Hard Drive With Disk Utility

Easily add a new partition in various macOS or OS X versions

The Mac's Disk Utility app is a multipurpose, easy-to-use tool for working with hard drives and drive images. Among other things, Disk Utility can erase, format, repair, and partition hard drives. Here's a look at using Disk Utility to partition a Mac's hard drive quickly and easily.

Information in this article applies to Disk Utility on Macs running OS X Yosemite and El Capitan, as well as macOS Sierra, High Sierra, Mojave, and Catalina.

Disk Utility being used to erase a drive for macOS Sierra install

Use Disk Utility to Partition a Mac's Hard Drive

Disk Utility allows you to divide a hard drive into multiple partitions. Each partition can be formatted or left unformatted as free space for future use. The process differs with different iterations of the Disk Utility app in various versions of OS X and macOS.

Before you begin, make a backup of your data in case something goes awry, and delete files and applications you don't need to free up as much space as possible.

Partition With Disk Utility in OS X Yosemite

  1. Go to Applications > Utilities and double-click on Disk Utility to open the application.

  2. Select your machine's primary hard drive on the left pane.

  3. Select the Partition tab from the top menu next to First Aid.

  4. Under Position Layout, select the Plus sign (+).

  5. Decide what size you want the new partition to be. Choose to split the selected partition into two partitions or create a partition from unallocated space on the disk. Drag the bar to size the partition or use the Size field to type in the size.

  6. Type in a name for your new partition.

  7. Use the Format dropdown menu to select a format for this partition. The default format, Mac OS Extended (Journaled), is a good choice for most uses.

  8. Select Apply.

  9. Disk Utility will display a confirmation sheet, showing the actions it will take. Select Partition to continue.

  10. After a few moments, your new partition will appear mounted on your drive, ready to use.

Partition With Disk Utility in OS X El Capitan

Disk Utility got a makeover with El Capitan, so while it functions the same, some of the processes look different. For example, Disk Utility in El Capitan uses a pie chart to indicate the disk partitions.

  1. Go to Applications > Utilities and double-click on Disk Utility to open the application.

  2. Select the drive you want to partition in the left pane.

  3. Select Partition from the top menu, next to First Aid, Erase, Mount, and Info.

  4. Select the Plus sign (+) to add a new partition and use the pie chart to size it. Alternatively, type the size in the Size field.

  5. Type in the name of the new partition.

  6. Use the Format dropdown menu to select a format for this partition. The default format, Mac OS Extended (Journaled), is a good choice for most uses.

  7. Select Apply. A box will appear that says Applying Changes to [your drive].

  8. Select Show Details to see more of the process.

  9. After a few moments, your new partition will appear mounted on your drive, ready to use.

Partition With Disk Utility in macOS Sierra, High Sierra, Mojave, and Catalina

Apple advises that if your system uses the Apple File System (APFS), you shouldn't partition your disk in most cases. Instead, create multiple APFS volumes within a single partition using Disk Utility.

  1. Open Disk Utility and select the drive you want to partition in the sidebar.

    When you select a volume that already has data on it, the pie chart shows a shaded area representing the amount of data on the volume and an unshaded area representing the amount of free space available for another volume.

  2. Select Partition and then select Partition again.

  3. Select the Plus sign (+).

  4. Type a name for the partition in the Name field.

  5. Choose a file system format.

  6. Enter the size or drag the resize control to increase or decrease the size of the partition.

  7. Select Apply > Partition, and then select Continue.

  8. Select Show Details to view more information about the process.

  9. After a new partition is created, select Done.

  10. You'll now see an icon for the new partition in both the Disk Utility sidebar and the Finder sidebar.