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.