Proportio — Rule of Three

Looking for 5 different apps for your everyday calculations?

Proportio replaces them all. One app, 5 tools, zero hassle.

CALCULATOR — Instant rule of three. Fill in 3 values, the 4th appears automatically. Copy the result in one tap. Find your calculations in the history.

RECIPES — Create your recipes, change the portions: all quantities adjust automatically. Recipe for 4? Switch to 7 in one gesture. No other rule of three app does this.

PERCENTAGES — Discount, tax, tip, increase, margin. The fastest percentage calculator you've ever tried.

CONVERSIONS — Weight, volume, temperature, length. Metric and imperial. No more Google tabs.

PROFILE — Dark mode, French and English, unit system choice.

WHY PROPORTIO OVER ANOTHER APP?
→ 5 tools instead of one
→ Modern design, built for one-handed use
→ Works offline, no account required
→ No personal data collected
→ Instant calculations, no "Calculate" button to find

Proportio is free. If you like the app, you can support me for the price of a coffee (€2.49) — it removes ads and unlocks unlimited recipes.

Students, cooks, DIYers, pros: Proportio simplifies your daily calculations.