Which browser tab is using the most memory? How to find it in Chrome, Safari, Firefox, Arc and Edge

Why one tab can take 2 GB

Every modern browser runs each site in its own process, partly for security and partly so one crashing page cannot take down the rest. That is why Activity Monitor shows a dozen "Google Chrome Helper (Renderer)" or "Safari Web Content" entries instead of one browser. It also means a tab is a program, with its own memory, and some programs are big.

A plain article page costs 50 to 150 MB: the HTML, the images decoded into bitmaps, the fonts, the JavaScript engine's working memory. Then there are the pages that are really applications. Gmail, Google Docs, Figma, Notion, Slack, a Jira board, a trading dashboard, a 4K YouTube video: these load megabytes of script, keep large data structures in memory, decode video frames, and grow as you use them. Half a gigabyte is normal for one of these, and 1 to 2 GB is common for a Figma file or a long Google Sheet. A tab left open for days accumulates more, because web apps leak a little with every action and the only thing that clears it is a reload.

Two more things inflate the figure. Video keeps decoded frames in memory and a tab playing 1080p video typically runs 300 to 600 MB. Extensions run inside every page that matches their rules, so an ad blocker or a password manager adds its own slice to each tab; a Hacker News thread linked below measured ad-block extensions as a major share of the per-tab total. Chrome's Task Manager lists extensions as their own rows, which makes the hidden cost visible.

None of this is a bug. The bug is when a tab you are not using still holds that memory, which is the state macOS calls memory pressure and the state your Mac is in when the beachball appears while switching apps. The browser-specific steps below find the tab. Our guide to what memory pressure means explains why 8 GB Macs feel it first.

What tabs typically cost

Approximate memory footprint per tab, as Chrome's Task Manager and Activity Monitor report it. Measured values vary with screen size, extensions and how long the tab has been open, but the ranking holds.

The sum matters more than any single bar. Thirty ordinary tabs at 100 MB each is 3 GB before a single web app is open, and on an 8 GB Mac that is already into swap. The point of finding the biggest tab is that one 2 GB tab is faster to fix than thirty small ones.

Chrome: the built-in Task Manager

Chrome has had its own Task Manager since the beginning, and on a Mac it lives in the Window menu (Window, Task Manager). There is no keyboard shortcut on macOS; Shift + Esc only works on Windows, Linux and ChromeOS, which is why so many guides send Mac users to a shortcut that does nothing. You can also reach it from the three-dot menu, More Tools, Task Manager.

The window lists every process Chrome is running: rows beginning Tab: are pages, Extension: rows are extensions, Subframe: rows are embedded content such as ads and video players, and the rest are Chrome's own services. Click the Memory footprint column header to sort by it; click again to put the largest at the top. The top Tab row is your answer. Select it and click End Process to kill just that page (it turns into a "snap" error page you can reload later), or switch to it and close it normally.

Three other Chrome tools help. Memory Saver (chrome://settings/performance) automatically unloads tabs you have not looked at for a while, keeping the tab in the bar but freeing its memory until you click it; Google says it uses up to 40 percent less memory with it on. Hovering over a tab shows its memory use in the tooltip in recent versions. And chrome://discards lists every tab with Chrome's own estimate of how safely it can be unloaded, and lets you discard one by hand.

Arc, Edge, Brave, Vivaldi and Opera are all built on Chromium and have the same Task Manager under slightly different menus (Edge: three-dot menu, More tools, Browser task manager; Arc: the Window menu or Command + Option + Esc inside Arc). Arc also archives tabs automatically after 12 hours by default, which is Memory Saver with a different name.

Safari: Activity Monitor shows each tab by name

Safari has no task manager of its own, but it does not need one, because macOS's Activity Monitor already splits it up. Open Activity Monitor (Spotlight, type the name), click the Memory tab, and type Safari in the search field. You will see one Safari row (the app itself, usually 200 to 500 MB) plus a Safari Web Content row for each open site. Since macOS Monterey each of those rows is named after the page it is running, so the list reads "Safari Web Content (YouTube)", "Safari Web Content (Gmail)" and so on. Sort by the Memory column and the top one is the tab.

Two things are worth knowing. Safari keeps a Web Content process alive for a tab as long as the tab exists, even if you have not looked at it for days; Howard Oakley's test, linked in the sources, measured about 120 MB per tab on average and found the processes stay resident until Safari quits. Closing the tab ends its process immediately. And when a page gets large, Safari shows a yellow bar at the top reading "This webpage is using significant memory. Closing it may improve the responsiveness of your Mac." That bar is Safari naming the tab for you; reload or close it.

If you want more detail, turn on the Develop menu (Safari, Settings, Advanced, Show features for web developers), then Develop, Show Web Inspector on the heavy tab and open the Timelines tab, which records memory over time. For the ordinary question of "which tab", Activity Monitor is enough. The process pages on WebKit Web Content and WebKit Networking cover what those rows do and when they are safe to quit.

Firefox: about:processes and about:memory

Type about:processes into the Firefox address bar. It lists every process with the tabs inside it, memory and CPU per row, and a close button next to each tab that unloads it in place. Hover a row for the tab titles if several share a process. For a deeper breakdown, about:memory and its Measure button produce a full tree of where every megabyte is, which is more than most people need but is the ground truth when a site's own script is leaking.

Firefox has unloaded tabs automatically when memory runs low since version 93, and about:unloads shows which tab it would unload next and lets you do it by hand. The Firefox Task Manager also lives under the three-line menu, More tools, Task Manager, and is the same view as about:processes.

Is the browser actually the problem on your Mac?

Before closing tabs, check whether the Mac is under memory pressure at all. A browser using 6 GB on a 32 GB Mac is fine; the same 6 GB on an 8 GB Mac is the beachball. Enter what Activity Monitor shows and the widget tells you which side of that line you are on.

Green pressure with a big browser number means the memory is being used, not wasted; macOS gives idle memory to whoever asks and takes it back when needed. Yellow or red with a browser at the top of the list is the case where finding the tab pays off. The "your system has run out of application memory" page covers the extreme version, where macOS asks you to force quit apps outright.

What to do about a memory-hungry tab, in order

Least disruptive first. Most of the time the first two steps are the whole fix.

1. Find the biggest tab

   Chrome, Arc, Edge: Window menu, Task Manager, sort by Memory footprint. Safari: Activity Monitor, Memory tab, search Safari, sort by Memory. Firefox: about:processes. Note the top one or two tabs.

2. Reload it

   If it is a web app you are using (Gmail, Slack, Figma), reload the page with Command + R. Memory drops to the fresh-load figure, usually a third of what a days-old tab holds. Everything you need is on the server.

3. Close what you are not using

   Tabs you opened to read later are not free. Bookmark them (Command + D) or use a reading list, then close them. Pinned and background tabs still hold memory in Safari until closed.

4. Turn on the browser's tab unloading

   Chrome: chrome://settings/performance, Memory Saver on. Edge: Settings, System and performance, Sleeping tabs. Arc: Settings, auto-archive. Firefox does it automatically. Safari has no equivalent, so closing is the only option there.

5. Check extensions

   In Chrome's Task Manager, sort by Memory footprint and look at the Extension: rows. Any one over 100 MB, or any you do not recognize, is worth disabling (chrome://extensions). Fewer extensions means less memory in every tab, not just one.

6. Quit and relaunch the browser

   Command + Q, then reopen. All browsers restore tabs; Safari and Chrome reload only the ones you click. A browser that has been open for a week often drops several GB on relaunch.

7. Watch for the tab that grows

   If the same site climbs past 1 GB every day, it is leaking. Report it, use the site's native app instead if there is one, or keep it in its own window you can close between sessions. Safe to Quit tracks each process over hours and flags the ones that only ever grow, which is the pattern a leak makes.

When tab memory is a sign of something else

Most of the time a heavy tab is just a heavy page. There are a few patterns that mean more.

• Memory climbs with no tab open. A Safari or Chrome process growing while every tab is closed, as in the Apple Community thread quoted below, points at an extension or a broken sync process rather than a page. Disable extensions, then test.
• One Web Content process at 10 GB or more. That is not a page using memory; it is a runaway script or a rendering bug. Kill that process from Activity Monitor (it only affects that tab), reload, and if it recurs on the same site, the site is at fault.
• Swap used grows every day on an 8 GB or 16 GB Mac. The browser is probably the biggest single consumer, but the fix is to close the apps you forgot about too. Activity Monitor's Memory tab shows Swap Used at the bottom; see what a healthy swap figure looks like.
• Everything is fine until a video call. Zoom, Teams and Meet in a browser tab each take 500 MB to 1 GB and the CPU to go with it. Use the native app, or close the other heavy tabs first.