Fastest path: If you have videos and photos, start with compression — it recovers the most space with the least effort. For everything else, old device backups and app caches are the quickest wins.
Free Up Storage on Mac
Methods ranked by actual impact. Start at the top and work down — most people can recover 50–150 GB before they even reach method 4.
Compress your video library
Videos are almost always the biggest space hog. A 4K iPhone clip is 400 MB. Compressed with no visible quality loss, it's 40–60 MB. If you have a few years of family videos or any video projects, this alone can recover 50–150 GB.
Use MediaOptim — drag your video folder, set quality, let it run overnight.
Compress with MediaOptimCompress your Photos library
iPhone photos are large HEIC files. A 150 GB Photos library compresses to 60–80 GB. Every photo stays in your library, organized the same way — just smaller.
Delete old iPhone/iPad backups
Each iTunes/Finder backup is 5–15 GB. Open Finder → your device → Manage Backups. Keep the most recent one, delete everything else.
Enable Optimize Mac Storage
macOS offloads files you haven't opened recently to iCloud. Go to System Settings → [Your Name] → iCloud → iCloud Drive → Optimize Mac Storage. Requires available iCloud storage.
Clear app caches and browser data
Browser caches, app logs, and temporary files accumulate to 5–15 GB on an active machine. Navigate to ~/Library/Caches and delete folders for apps you recognize.
Delete Time Machine local snapshots
macOS keeps local snapshots that don't show in Finder. Run: sudo tmutil deletelocalsnapshots / in Terminal. Your actual files are untouched.
Clear Xcode derived data (developers)
Navigate to ~/Library/Developer/Xcode/DerivedData and delete everything. Xcode rebuilds it automatically. Also check iOS DeviceSupport for old version folders.
Remove large forgotten files
Go to System Settings → General → Storage → Storage Settings → Review Files. Sort by size. Old disk images, downloaded installers, and forgotten archives often surface here.
Realistic Expectations
Following methods 1–5 typically frees 50–150 GB on a Mac that's been in use for 2+ years. The exact amount depends on how many videos and photos you have.
If you've done all of these and still need more space, the next step is either an external drive or revisiting whether your Mac has the right storage for your needs.