I started Calc because I kept running into the same problem: online calculators often give you a number, but not enough information to understand whether that number can actually be trusted. I wanted to build calculators that show their work: the formula, assumptions, limits, sources, and the exact inputs used to produce the result. What started as a small collection of practical calculators gradually evolved into a much more systematic project. We began separating exact calculations from estimates, versioning formulas, adding source checks, reverse calculations, shareable result receipts, and independent verification of the calculation logic. Calc covers practical everyday problems across money, business, home renovation, energy, cars, logistics, dates, and digital tools. It currently supports Ukrainian and English, with Polish, Spanish, Portuguese, German, and French localization planned next. The long-term goal is to make Calc useful across languages without turning localization into simple translation. Formulas, units, terminology, assumptions, and local data should make sense for the person actually using the calculator. The idea is simple: not just to give people an answer, but to make the answer understandable and verifiable.

calc

Calculators that show their work

Calculators that show their work