Clearing the invisible layer: a complete guide to caches on your Mac
Caches are temporary files that apps and macOS save so things load faster next time. That's useful — until they pile up to 10, 20, even 30 GB and start eating into your storage. The good news: every cache on your Mac is safe to delete because it will rebuild itself automatically. Here's how to clear each type.
Browser cache
Your browser stores copies of every image, script, and stylesheet from every website you visit. After months of browsing, this can reach several gigabytes.
Safari
- Open Safari and go to Settings → Advanced.
- Check Show features for web developers (this adds the Develop menu).
- In the menu bar, click Develop → Empty Caches.
This clears Safari's cached website data without touching your bookmarks, history, or saved passwords.
Chrome
- Press Cmd + Shift + Delete to open the Clear Browsing Data panel.
- Set the time range to All time.
- Check Cached images and files (uncheck the rest if you want to keep history and cookies).
- Click Clear data.
Firefox
- Open Settings → Privacy & Security.
- Scroll to Cookies and Site Data and click Clear Data.
- Check Cached Web Content and click Clear.
After clearing browser cache, websites may take an extra second to load on the first visit. Everything returns to normal speed after that.
App caches
Every app on your Mac keeps its own cache folder at ~/Library/Caches. Spotify buffers music. Slack stores images from every channel. Design tools keep rendered previews. Together, app caches can quietly grow to 5–20 GB.
To clear them manually:
- Open Finder, press Cmd + Shift + G, and type
~/Library/Caches. - Sort by size to find the biggest folders.
- Delete the contents of individual app cache folders (not the folder itself — just what's inside).
/System/Library/Caches — that's managed by macOS itself.System cache
macOS maintains its own caches for things like fonts, kernel extensions, and system services. These live in /Library/Caches (not your user Library). In most cases they're small — a few hundred megabytes — and macOS handles their lifecycle automatically.
You generally don't need to touch system caches. If you suspect corruption (a font not rendering, a service behaving oddly), a restart clears most of them. For a deeper reset, macOS rebuilds system caches fresh after a restart in Safe Mode.
DNS cache
Your Mac remembers website addresses it has looked up recently. If a website moved to a new server and your Mac still remembers the old address, flushing the DNS cache fixes it:
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
This doesn't free disk space (the DNS cache is tiny), but it solves "website won't load even though it works on my phone" problems.
How much space can you expect to recover?
| Cache type | Typical size | Rebuilds? |
|---|---|---|
| Browser cache (all browsers) | 1–5 GB | Yes, as you browse |
| App caches (~/Library/Caches) | 5–20 GB | Yes, on next app launch |
| System caches | 0.2–1 GB | Yes, automatically |
| DNS cache | A few KB | Yes, instantly |
Total recovery depends on how long your Mac has been running without a cleanup. On a machine that hasn't been cleared in a year or more, 10–25 GB is realistic.
Caches rebuild themselves — is clearing them pointless?
Not at all. Caches grow because every app keeps adding to them but few ever prune old entries. Clearing them is like resetting a counter: you get the space back now, and the cache slowly refills only with things you actually use. The rebuild rarely brings it back to the old size because you're not revisiting every website and file from the past year.
That said, clearing caches every week is overkill. Once every few months — or when you need a quick chunk of free space — is a sensible rhythm.
If you're looking for more ways beyond caches, our guide on how to free up space on Mac covers 12 methods including snapshots, old backups, and app leftovers. And if your storage bar shows a large "System Data" category, see what System Data on Mac actually is.
Let your Mac clean itself
Gigatidy scans your caches, explains what each one is in plain English, and lets you clear them in one click. Coming soon to the Mac App Store.
Meet Gigatidy →FAQ
Will clearing cache delete my passwords or bookmarks?
No. Cached files are temporary copies of website assets and app data. Your saved passwords, bookmarks, and documents are stored separately and are not affected.
Is it safe to delete everything in ~/Library/Caches?
Yes — those are user-level app caches and every one rebuilds automatically. Just quit running apps first, and delete folder contents rather than the folders themselves.
How often should I clear my Mac's cache?
Every few months is reasonable, or whenever you need a quick burst of free space. Doing it weekly doesn't help much because caches need time to grow before they're worth clearing again.