Free · No Download · Works on Any Device
The Calculator
App
130+ free calculators for finance, mortgage, savings, everyday maths, and unit conversion. No download. No account. Add to your homescreen for a full app experience on iPhone or Android.
Why people use The Calculator App
Instant results
Every calculator updates in real time as you type — no submit button needed.
Works like an app
Add to your homescreen on iPhone or Android. Launches fullscreen with no browser bar.
No download needed
130+ calculators available instantly in your browser. No App Store, no install, no storage used.
No account required
Fully free. No sign-up, no ads, no data collection. Just calculators.
UK-focused
Built for UK users — PAYE tax, National Insurance, ISAs, Stamp Duty, and more.
Works offline
Once loaded, the app works without an internet connection on supported devices.
Popular calculators in the app
How to install
Add to Homescreen
iPhone / Safari
- 01Open thecalculatorapp.org in Safari
- 02Tap the Share button (box with arrow at bottom of screen)
- 03Scroll down and tap "Add to Home Screen"
- 04Tap Add — the app icon appears on your homescreen
- 05Launch it — it opens fullscreen like a native app
Android / Chrome
- 01Open thecalculatorapp.org in Chrome
- 02Tap the three-dot menu (top right)
- 03Tap "Add to Home screen"
- 04Tap Add — it installs as a PWA app
- 05Launch from your homescreen — runs as a standalone app
What is a PWA? A Progressive Web App (PWA) is a website that behaves like a native app. It installs from your browser with no App Store required, launches fullscreen without a URL bar, and can work offline once loaded. The Calculator App is a full PWA — free, instant, and available on every device.
The Calculator App vs other calculator apps
| Feature | The Calculator App | Typical app store app |
|---|---|---|
| Download required | No — runs in browser | Yes — App Store / Play Store |
| Number of calculators | 130+ | Usually 1–10 |
| UK-specific (PAYE, ISA, SDLT) | Yes | Rarely |
| Cost | Free, always | Often freemium or ad-supported |
| Works on iPhone & Android | Yes | Usually one platform |
| Storage used | ~0 MB | 10–50 MB |
| Account required | No | Often yes |
Frequently Asked Questions
Is The Calculator App really free?
Yes — completely free. No subscription, no in-app purchases, no ads. Every calculator on the site is free to use with no limits.
Do I need to download anything?
No. The Calculator App runs entirely in your browser. You can use it on any device without downloading anything from the App Store or Play Store. If you want it on your homescreen, use the 'Add to Home Screen' option in Safari or Chrome — it installs instantly.
Does it work on iPhone?
Yes. Open the site in Safari, tap the Share button, then 'Add to Home Screen'. It installs as a PWA app and launches fullscreen — it looks and feels identical to a native app.
Does it work on Android?
Yes. Open in Chrome, tap the three-dot menu, then 'Add to Home screen'. It installs as a PWA and runs standalone.
Does the calculator app work offline?
Yes — once you've loaded the site, most calculators work without an internet connection. The app uses service worker caching to store pages locally on your device.
How many calculators does it have?
130+ calculators and converters across finance (mortgage, salary, ISA, compound interest), everyday (percentage, tip, BMI, age), construction (gravel, concrete, mulch), and unit converters (weight, length, temperature, cooking).