Analyze any website's loading speed and performance in real time. Get actionable suggestions to improve
scores for both mobile and desktop experiences instantly.
Editor score is the AltFTool team’s own rating, not user reviews.
Highlights
Speed score
Suggestions
Mobile vs desktop
Features
What Website Performance Estimator does
Speed score
Suggestions
Mobile vs desktop
Install
How to install Website Performance Estimator
1
Step 1: Open the extension's page on AltFTool and choose “Add to Chrome”. The official Chrome Web Store listing opens in a new tab.
2
Step 2: On the store listing, check the developer, the description and the permissions the extension asks for.
3
Step 3: Click “Add to Chrome”, read the permission prompt Chrome shows, then confirm with “Add extension”.
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Step 4: Pin it. Open the puzzle-piece Extensions menu next to the address bar and click the pin icon so it stays one click away.
Using Edge, Brave or Opera?
Microsoft Edge, Brave, Opera and Vivaldi are built on Chromium and can install most Chrome Web Store extensions.
In Edge, open the store listing and allow “extensions from other stores” when Edge asks, then click “Get” / “Add to Chrome”.
Firefox and Safari use a different extension format, so Chrome Web Store items do not install there.
Permissions & privacy
What it can access
Check before you install
Chrome shows the exact permissions Website Performance Estimator asks for before you confirm the install. You can also read them, and the developer’s data declarations, in the Privacy practices section of the store listing.
Read the permissions.“Read and change all your data on all websites” is powerful. Prefer extensions that only ask for what their job needs, such as activeTab or storage.
Check the developer and privacy tab.Every Chrome Web Store listing has a Privacy practices section where the developer declares what data, if any, is collected.
Install from the official store.Avoid .crx files from random download sites. Our pages only link to the official Chrome Web Store listing.
Prune what you don't use.Every extension adds a little start-up and memory cost. Remove the ones you haven't opened in a month from chrome://extensions.
FAQ
Website Performance Estimator questions
Is Website Performance Estimator free?
Yes. Website Performance Estimator is a free Chrome extension from AltFTool and does not need an AltFTool account.
How do I install Website Performance Estimator?
Choose “Add to Chrome” on this page to open the official Chrome Web Store listing, review the permissions, then click “Add extension” and pin it from the Extensions menu.
Does Website Performance Estimator work in Edge or Brave?
Website Performance Estimator is built for Google Chrome. Chromium-based browsers such as Microsoft Edge, Brave and Opera can usually install Chrome Web Store extensions too; Firefox and Safari cannot.
What can Website Performance Estimator do?
Speed score; Suggestions; Mobile vs desktop.
What permissions does Website Performance Estimator need?
Chrome shows the exact permissions before you confirm the install, and the store listing shows them too. Paste them into AltFTool's Browser Extension Permission Analyzer for a plain-English explanation.
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