Guide

Can you delete .dmg files after installing an app on a Mac?

Yes: once the app is in your Applications folder, eject the disk image and move the .dmg to the Trash.

The built-in way

Eject it, then trash it

Make sure the app is in Applications (drag it there from the disk image window if you haven’t).
In the Finder sidebar, click the eject button next to the disk image, or drag its icon on the Desktop to the Trash.
Select the .dmg file in Downloads and press ⌘⌫.

If the app runs from the disk image window instead of Applications, it isn’t installed yet. Copy it to Applications first.

Another way

Find every old installer at once

Open Downloads and press ⌘F. Set the search to "Downloads".
Click +, choose "Kind" is "Other", and type "Disk Image". Add another rule for installer packages if you like.
Select the ones you no longer need and move them to the Trash.

With Omaculate

Let Oma do it, and check her work first

Omaculate’s Trash old app installers recipe finds .dmg and .pkg files that have been in Downloads for more than 30 days and lists them for you to approve.

Recipe: Trash old app installers An installer in Downloads, older than 30 days, goes to the Trash.

Questions

Will deleting the .dmg uninstall the app?

No. The app lives in Applications. The .dmg is only the package it came in.

Should I keep .dmg files as a backup?

Rarely. You can download the installer again from the developer. Keep one only if the app is no longer available.

More guides

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Coming soon to the Mac App Store Needs macOS 15 Sequoia or later