The percentage calculator
that just makes sense.
Tips, discounts, increases, reverse percentages — Cento turns the maths you always second-guess into a clean, instant answer. No clutter. No ads. No account.
Built to be effortless
Everything you need to work with percentages, and nothing you don't.
Instant results
Type a number, get the answer. Live calculation as you type — no equals button to hunt for.
Four calculators in one
Percentage of a value, increase, decrease and reverse percentage — switch in a single tap.
History & recalculate
Every calculation is saved. Tap to recalculate, label it, or export your history as CSV/TXT.
Home Screen widget
Jump straight into any calculator from your Home Screen with a single tap.
19 languages
Fully localized — including right-to-left, CJK and Indic scripts. Cento speaks your language.
Private by design
100% on-device. No tracking, no analytics SDK, no account. Your numbers stay yours.
One app, every percentage problem
The four things people actually need a percentage calculator for.
Free to start. Pro forever.
No subscription. Unlock everything once and keep it.
- ✓ All four calculators — simple, increase, decrease, reverse
- ✓ Unlimited history with labels and tags
- ✓ Export your calculations to CSV or TXT
- ✓ No subscription, no renewals, no surprises
The free version includes the simple calculator and your most recent history — forever.
🔒 Your data never leaves your device
Cento stores every calculation locally on your iPhone. There is no server, no account, no advertising and no third-party analytics. Read exactly what we do — and don't do — in our Privacy Policy.