Are Chrome Extensions Slowing Down Your Computer? How to Find the One

Chrome extensions slowing down your computer is one of the quieter causes of a sluggish browser. Each extension seemed harmless when you installed it. Two years later you have fifteen, half of them run on every page you open, and Chrome feels heavier than it should.

You do not have to guess which one. Chrome measures each extension separately, and a simple halving test finds the culprit in a few minutes even when the numbers are close. This guide shows both.

The short answer#

• Measure first in Chrome's task manager: every extension has its own row.
• Test in Incognito to see whether extensions are the problem at all.
• Halve until you find it: turn off half, test, repeat.
• Limit site access for the extensions you keep.

What we measured on a Mac#

Tested on a MacBook Pro (M1 Pro) with 16 GB of RAM, macOS 26.3, Chromium 153 (the open-source build Chrome is made from, used because branded Chrome no longer loads test extensions from the command line), October 21, 2026. We opened the same five simple pages in a fresh profile twice: once with no extensions and once with three of our own extensions installed (Dark Mode, Draw on Web and Pixel Perfect Overlay). Two of them inject a script into every page. Memory is the total footprint of every Chrome process in a fresh test profile, read with macOS's footprint tool.

That is about 45 MB per extension before you do anything with them, plus one extra process each. Small extensions are cheap; twenty of them are not. Heavier extensions (ad blockers with big filter lists, shopping and AI helpers) cost more.

How do extensions slow Chrome down?#

Extensions cost resources in three ways:

1. Content scripts. Many extensions inject code into every page you open: ad blockers, grammar checkers, coupon finders, translators, password managers. That code runs in every tab, so ten tabs means ten copies of the work.
2. Background workers. An extension can keep a background process alive to listen for events, sync data or check prices. Chrome's task manager shows these as Extension: rows.
3. Network and page changes. Some extensions rewrite pages, inject banners or make extra requests, which slows page loads.

An extension that only does something when you click its icon costs almost nothing the rest of the time.

Is it an extension at all?#

Open the slow site in an Incognito window: Ctrl+Shift+N on Windows or Command+Shift+N on a Mac. Most extensions do not run in Incognito unless you allowed them.

• Fast in Incognito, slow in a normal window? An extension (or something stored in your profile) is involved. Keep reading.
• Slow in both? Extensions are probably not the cause. See why Chrome is so slow for the other usual suspects.

How do you see what each extension costs?#

1. Open Chrome's task manager: Shift+Esc on Windows, or the Window menu, then Task Manager on a Mac. Google's speed-up guide also reaches it from the three-dot menu, then More tools, then Task Manager.
2. Sort by Memory footprint, then by CPU.
3. Look at rows starting with Extension:. Those are background processes. Rows marked Background page are worth a close look, as Google's help page points out.
4. Use Chrome normally for a minute and watch. An extension row that stays busy while you are not using it is costing you.

Content scripts do not get their own row; their cost is added to each Tab: row. That is why the halving method below is still useful.

The halving method#

When no single row stands out, test by elimination:

1. Go to chrome://extensions and write down which extensions are on.
2. Turn off half of them.
3. Use Chrome the way that felt slow for five minutes.
4. Faster? The culprit is in the half you turned off. Turn that half back on and turn off half of it.
5. Same? The culprit is in the half still on. Turn off half of those.
6. Repeat until one extension is left.

With sixteen extensions, this takes four rounds.

What to do with the culprit#

• Update it. On chrome://extensions, turn on Developer mode, click Update, then turn Developer mode off.
• Restrict it to the sites where you need it (next section).
• Replace it with a lighter one that does only what you use.
• Remove it. If you have not used it in a month, you will not miss it.

Remember that older Manifest V2 extensions stopped running in Chrome in 2025 and were removed from the Chrome Web Store in 2026. If an old favorite was replaced by a new version, the new one may behave differently; check its settings.

Make the keepers cheaper#

For each extension you keep:

1. On chrome://extensions, click Details.
2. Under Site access, choose On click or On specific sites instead of On all sites.
3. Turn off Allow in Incognito unless you really need it.

An extension restricted to three sites does no work on the other forty tabs. This also limits what it can read, which is better for privacy.

A quick checklist for every extension#

How we built ours to stay light#

We make Cleaner, a Chrome extension that clears cache and cookies for one site at a time and, in the Pro version, puts idle tabs to sleep after 30 minutes and closes duplicate tabs. It does its work when you click it or on a schedule you set, and makes no network requests at all unless you enter a Pro key. If you suspect an extension is slowing Chrome, the free Tab Manager side panel in Cleaner sorts your tabs by estimated memory, which helps you see whether the weight is in tabs or elsewhere.

The bottom line#

Extensions can slow Chrome down, but only some do. Test in Incognito, measure in Chrome's task manager, halve your extension list until the culprit shows itself, and restrict the ones you keep to the sites that need them. For memory problems beyond extensions, see Chrome using too much memory.