Browsers slow down for reasons nobody can see, and extensions are the main one. The count creeps up and never comes down: a coupon finder from 2023, three PDF tools, two VPNs that fight each other, a tab manager you stopped opening in March. Each of them can inject code into every page you load.
Count what you actually have installed
Open the manager directly rather than hunting through menus.
- Chrome: chrome://extensions
- Edge: edge://extensions
- Firefox: about:addons, or ⌘⇧A / Ctrl+Shift+A
- Safari: Safari → Settings → Extensions, which only appears after the first one is installed
Most people guess four or five and find twelve to twenty. Leave Developer mode switched off while you work, so unpacked experiments do not get mixed in with the real list.
Let the browser’s own task manager pick the victims
Every Chromium browser ships a task manager showing what each extension costs right now. In Chrome press Shift+Esc, or go ⋮ → More tools → Task manager. Right-click the column header and add Memory footprint and CPU, then sort by memory. Extension processes are named after the extension, so there is no guessing.
Judge by category, because the numbers are consistent inside one. Shopping and coupon extensions routinely hold 150–400 MB per store page they touch, since they inject a comparison script into every product listing. Content blockers are cheap at idle, a few tens of MB. Screenshot and grammar tools land in between. Firefox shows the same thing at about:processes; in Safari, extensions hide inside Safari Web Content processes in Activity Monitor and are much harder to isolate.
Keep the few that do real work
A defensible list is short: a password manager, one content blocker, and one tool you used this week.
- Cut duplicate function. Two VPN extensions, three screenshot tools, or a dark-mode extension in a browser that already has a dark theme — each pair is pure overhead.
- Retire the dead ones. Chrome completed the move off Manifest V2, which disabled a generation of older ad blockers. Anything labelled “no longer supported” on the extensions page is doing nothing but taking up a row.
- Question the coupon category. It is the largest single source of both memory use and privacy complaints, and the codes it finds are usually offered at checkout anyway.
- Cap the total at eight. Beyond that the new tab page and toolbar both start to feel sticky, and you stop recognising what is installed.
Disable in small groups and measure
Do not remove twelve things at once. You will not know what fixed the problem, or what you actually miss.
Turn off three, quit the browser completely rather than closing the window, then load a heavy page such as a news homepage and compare the memory figure. Two things to keep in mind when reading the result: most extensions cost page-load time and RAM rather than benchmark points, so a browser that felt slow at forty tabs may test identically on a blank page. And Chrome’s Settings → Performance → Memory Saver, which discards inactive tabs, often recovers more than the whole cleanup on an 8 GB laptop. Enable it for sites you do not keep signed in to.
If you want a true baseline, open a guest window or a fresh profile with nothing installed and compare the two side by side.
Reduce permissions and stop the list growing back
Removal is not the only option. A screenshot tool does not need to read every page you visit; it needs to run when you click it. In Chrome go to chrome://extensions → Details on the extension → Site access → On click. Firefox exposes the same control on the extension’s Permissions tab, Safari under Settings → Extensions → per-site access. This blocks the content scripts that actually cost CPU, and it is the step almost everyone skips. While you are there, switch off “Allow in Incognito” for anything that does not need it.
Then set a rule for new installs: nothing gets added unless it solves a problem you hit twice this month, and task-specific tools — PDF converters, colour pickers, format converters — are removed the day the task ends. Review the list once a quarter. If you are signed in to sync, a removal on the laptop propagates to the desktop and phone, so the cleanup only has to happen once.
Two related jobs make more difference than they sound: clearing the cache without signing out of everything, and cutting tab clutter without losing pages you meant to read. Google’s own extension management page covers the remove and disable controls if a menu has shifted.