How to create a bootable macOS USB installer

Ready-to-paste createinstallmedia commands for every macOS version from Mavericks onward.

A bootable USB installer lets you install macOS on several Macs, erase a Mac completely, or install an older version than the one you're running. You'll need:

A USB flash drive or external disk: at least 32 GB for recent versions, 16 GB for older ones. It will be erased.
The full installer app for the version you want, in your Applications folder. Find it on the version pages or use the Terminal method.

1. Name the drive

Open Disk Utility, select the USB drive, click Erase, name it MyVolume, and choose Mac OS Extended (Journaled) with GUID Partition Map.

2. Run createinstallmedia

Paste the command for your version into Terminal, press Return, and enter your administrator password. Type Y when it asks to erase the volume. It takes 10–30 minutes.

macOS Golden Gate 27

sudo /Applications/Install\ macOS\ Golden\ Gate.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Tahoe 26

sudo /Applications/Install\ macOS\ Tahoe.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Sequoia 15

sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Sonoma 14

sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Ventura 13

sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Monterey 12

sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Big Sur 11

sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Catalina 10.15

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Mojave 10.14

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS High Sierra 10.13

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Sierra 10.12

sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app

OS X El Capitan 10.11

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

OS X Yosemite 10.10

sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ Yosemite.app

OS X Mavericks 10.9

sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ Mavericks.app

Lion and Mountain Lion predate createinstallmedia. For those, restore InstallESD.dmg (inside the installer app's Contents/SharedSupport folder) to the USB drive using Disk Utility.

3. Boot from the USB drive

Apple silicon: shut down, then press and hold the power button until you see startup options. Select the USB installer and click Continue.
Intel: restart while holding the Option (⌥) key, then choose the USB installer.

Intel Macs with the Apple T2 Security Chip may need Allow booting from external media turned on in Startup Security Utility first.

Apple's own instructions: Create a bootable installer for macOS.