tonyzedginidze / librecalculator

Libre Calculator 
The universe in numbers. 
Building the world's best calculators, free and open source.
Website · Download · Calculator packs · Get started · Ways to help · Docs
## Why Libre Calculator
 Explains every answer 
Each result shows the steps that produced it, with a diagram and a short lesson underneath.
- Steps use your inputs, not a generic example
- Answer, steps and diagram come from one calculation
- Lessons explain the idea behind the formula
 Packs you switch on 
Core is always on. Turn on health, cooking, construction and the rest when you need them.
- Every calculator has its own page on the web
- Active packs are cached for offline use
- The catalog is built to grow to thousands
 Web and desktop 
Use it at librecalculator.com, or run the desktop app. Cmd/Ctrl Shift C opens a quick panel from anywhere to find a calculator.
- Static website, one page per calculator
- Desktop app built with Tauri
- Same calculators and design on both
 Exact by contract 
Engines are pure functions with written numeric contracts and fixture tests. Arithmetic runs on 50-digit decimals and is rounded only for display.
- Contracts per domain in `docs/`
- Every engine has fixture tests in `bun test`
- Invalid input fails clearly instead of guessing
## Desktop app
Every calculator in a window of its own. Press Cmd/Ctrl Shift C in any app, type a few letters, and the calculator opens.
Free and open source. librecalculator.com/download picks the right file for your computer.
## Calculator packs
 See every calculator 
| Pack | Calculators |
|---|---|
| **Core** | Percentage, Percentage change, Fraction, Unit conversion, Area, Volume, Pythagorean theorem, Compound interest, Loan payment, Tip splitting |
| **Construction** | Concrete slab, Paint, Flooring, Roof area, Tile, Board foot |
| **Cooking and food** | Recipe scaling, Cups to grams, Oven temperature, Baker's percentage, Calories per serving |
| **Date and time** | Age, Date difference, Days until, Work hours, Time zone converter |
| **Education** | GPA, Grade, Final grade, Test score |
| **Finance** | Mortgage, Savings, ROI, Salary to hourly, Margin and markup, Inflation, Retirement savings |
| **Geometry** | Rectangle, Triangle, Circle, Sphere, Cylinder |
| **Health and body** | BMI, Resting energy (BMR), Daily energy (TDEE), Macros, Body fat estimate, Water intake, Weight at a chosen BMI |
| **Math and everyday** | Discount, Mean, median and mode, Standard deviation, Ratio, Scientific functions, Random number picker, Fuel economy |
| **Physics** | Speed, Force, Kinetic energy, Power, Density, Pressure |
| **Statistics** | Z-score, Confidence interval, Probability, Weighted average |
| **Units and conversion** | Length, Mass and weight, Temperature, Speed, Time duration, Cooking measures |
## Get started
The quickest way is the website: librecalculator.com.
Or get the desktop app for macOS, Windows (x64 and ARM) and Linux (deb, rpm and AppImage, x64 and ARM). Every build is also on the releases p