A calculator for every question,
right in your browser.
The Best Calculators Chrome extension puts a full numeric calculator — plus 12 specialized tools for finance, health, and math — in a persistent sidebar. Open it once, keep it open all day.
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Everything you need, nothing you don't
Built to be fast, private, and always one click away.
Full numeric calculator
Keyboard-friendly calculator always ready in the sidebar. Type equations directly — digits, operators, Enter, Backspace all work.
Stays open while you browse
Unlike a popup, the side panel persists as you navigate. Keep a mortgage calculation open while you read listings.
Star your favorites
Pin the calculators you use most to the top of the list. Stars are saved across sessions.
Search bestcalculators.app
Can't find what you need in the 12 built-in tools? Search the full site without leaving your current tab.
Instant results
Every calculation updates in real time as you type. No submit button, no loading spinner.
Privacy first
All calculations run locally in your browser. Nothing is ever sent to a server.
12 specialized calculators, built in
No internet connection needed for these — they run entirely in the extension.
Need more? Search the full library from inside the extension.
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How to install
- 1
Click “Add to Chrome”
Open the Chrome Web Store listing and click the blue “Add to Chrome” button.
- 2
Confirm the install
Chrome will ask you to confirm. Click “Add extension” — no permissions beyond local storage are required.
- 3
Pin the icon
Click the puzzle-piece Extensions icon in your toolbar, find Best Calculators, and click the pin icon so it’s always visible.
- 4
Open the side panel
Click the Best Calculators icon in your toolbar. The side panel opens on the right and stays open as you browse.
Frequently asked questions
Is the Best Calculators extension free?
Yes, completely free. No subscription, no in-app purchases, no account required.
Which browsers does it work in?
The extension is built for Chrome (version 114 and later). It uses the Chrome Side Panel API which is not available in other browsers.
How do I open the extension?
Click the Best Calculators icon in your Chrome toolbar. The side panel opens on the right side of your browser window and stays open as you browse.
Can I use my keyboard with the calculator?
Yes. When the side panel is focused, you can type digits, use +, -, *, / for operators, Enter or = to evaluate, Backspace to delete, and Escape to clear.
What calculators are built in?
The extension includes a standard numeric calculator plus 12 specialized calculators: Compound Interest, Mortgage, Loan Payment, Tip, ROI, Discount, Salary to Hourly, BMI, Calorie, Percentage Change, Pythagorean Theorem, and Square Root.
Can I access more calculators?
Yes. Use the search bar in the extension to find any calculator on bestcalculators.app — results link directly to the full calculator page.
Does the extension track my calculations?
No. All calculations happen locally in your browser. No data is sent to any server.
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Ready to try it?
Free, no account required. Install in under 30 seconds.
Add to Chrome — It's Free