If you've switched to Safari specifically to reduce memory pressure on your Mac, you made a sensible choice. Safari uses significantly less RAM than Chrome for the same browsing session, and Apple keeps optimising it with every macOS release. For day-to-day browsing, it's the right call.
But memory pressure doesn't always come from Safari's architecture. Sometimes it creeps up slowly over hours, even when you haven't opened any new tabs. When that happens, the culprit is usually a memory leak, and understanding what that means makes it much easier to fix.
What's a memory leak, plainly?
RAM (random-access memory) is the temporary workspace your Mac uses to hold whatever's currently running. Think of it like a desk: apps pick up pieces of paper to work with, and when they're done they should put the paper back in the drawer. A memory leak is what happens when an app picks up paper but never puts it back.
With a leak, memory use grows over time even though you're not doing anything new. An app that used 400 MB when you opened it might use 800 MB an hour later, then 1.2 GB the hour after that, without you having done anything to justify the increase. The app is asking macOS for more workspace but never returning what it's finished with.
The reason this matters is that macOS has a finite amount of RAM. Once memory is fully committed, your Mac starts memory swapping: moving data from the fast RAM onto the much-slower SSD to make room. That's the point where you feel things slow down. Tabs take a moment to reload, apps are sluggish to respond, and the general feeling is that your Mac is dragging. For a deeper look at what happens at that threshold, see what memory pressure means on Mac.
Does Safari really leak memory?
Yes, though less often than you might expect, and the leak usually isn't in Safari itself.
Safari, as a browser, is Apple's product and it benefits from tight integration with macOS memory management. Apple actively fixes Safari memory bugs in point releases. If you're running macOS Sequoia or Tahoe, keeping your system updated is one of the most reliable ways to avoid known Safari leaks, because Apple patches them relatively quickly once identified.
The more common source is the web apps running inside Safari. Modern web apps like Google Docs, Figma, Gmail's full client, and Notion are highly complex pieces of software running inside the browser. They manage their own memory internally, and when they have a bug, that bug expresses itself as a growing memory footprint inside Safari's process. From your Mac's perspective, Safari is the one using more and more RAM. But the actual problem is in the JavaScript running inside the tab.
Extensions are the other common contributor. Each Safari extension runs its own process alongside Safari. A poorly written extension can grow in memory use over an open session in the same way a leaky web app can.
How to spot a Safari leak
The clearest way to check is Activity Monitor. Press Command-Space, type "Activity Monitor", and press Return. Click the Memory tab. You'll see a list of processes and their memory use.
Look for entries named Safari and Safari Web Content. There will often be several Safari Web Content entries, one per tab or tab group. The total across all of them is Safari's real memory footprint.
A reasonable range for active Safari use across many tabs is 4-6 GB. If you're above 8 GB and it's been climbing over the course of a few hours, something is leaking. To narrow it down, start closing tabs and watch whether any Safari Web Content process drops significantly. The one that was holding a lot of memory and releases it when you close the tab is almost certainly your culprit.
Also look at the Memory Pressure graph at the bottom of the Memory tab. Green means your Mac is coping. Yellow means it's working harder than it should. Red means it's in active distress and swapping heavily to disk. If Safari's total is high and the graph is yellow or red, the two things are connected.
How to fix Safari memory issues
The fixes, in order of effort:
Quit Safari and reopen it. Press Command-Q to fully quit, not just close windows. This is the most complete reset available. When Safari relaunches, it starts fresh with no accumulated leaks. You can use "Reopen All Windows from Last Session" to get your tabs back. If memory pressure drops after doing this, you've confirmed a leak was present.
Close tabs you're not actively using. Each open tab holds its own slice of memory, and complex web apps hold a larger slice than simple pages. A Google Docs document held open for six hours is a much more likely leak source than a news article. Tab Groups in Safari help you organise tabs, but they don't free their memory, they keep the tabs in memory just as open tabs do. Closing the tab is the only way to release that memory.
Audit your extensions. Go to Safari > Settings > Extensions. Look at what you have installed. Disable any extension you don't actively use, then watch Activity Monitor over the next session. If Safari's memory stays flat, one of those extensions was leaking. You can re-enable them one at a time to find the specific one. Removing it entirely is the cleanest solution.
Clear website data. Go to Safari > Settings > Privacy > Manage Website Data. This clears cached data, cookies, and local storage for sites you've visited. It won't fix an active leak in a running tab, but it can reduce the baseline footprint of web apps the next time you open them and sometimes resolves persistent issues with specific sites.
Keep macOS updated. Go to System Settings > General > Software Update. Apple has shipped documented Safari leak fixes in Sequoia and Tahoe point releases. If you're running an older minor version of macOS, you may be affected by a known bug that's already been patched. Updating is low effort and sometimes solves the problem completely.
If you're trying to understand whether the problem is Safari specifically or your overall system, the companion post on why Chrome uses so much RAM on Mac is worth a read for context. And if you want a full walkthrough of freeing memory on Mac beyond just the browser, see how to reduce browser memory usage on Mac.
What's a normal amount of RAM for Safari to use?
Here's a realistic breakdown:
- Light browsing (5-10 simple tabs): 500 MB to 1.5 GB. News sites, search results, simple articles.
- Moderate use (10-20 tabs, some web apps): 2-4 GB. A reasonable mix of everyday browsing and productivity.
- Heavy use (20+ tabs, multiple complex web apps): 4-6 GB. Google Docs, Figma, Notion, Gmail, all open at once.
- Probable leak territory: above 8 GB sustained, especially if it keeps climbing over time without you opening new tabs.
Those top-end figures are fine on a Mac with 16 GB of RAM. On an 8 GB Mac, 6 GB in Safari alone leaves very little room for everything else your system needs to run. If that's your situation, being more disciplined about closing tabs you're not actively using is the most effective habit you can build.
For Apple's own guidance on when your Mac's RAM amount might genuinely be the limiting factor, the Activity Monitor: check if your Mac needs more RAM guide is worth bookmarking.