# calcu.lol

> Free multilingual visual calculators that help people understand math, not just get an answer. Every calculator is accurate, shareable by URL, and explains the result with a visualization. Available in 8 languages: English, Spanish, Chinese, Arabic, Portuguese, Japanese, French, and German.

calcu.lol is a public, free-to-use website with no accounts, no ads, no tracking cookies. All calculator state lives in the URL, so any result can be shared by copying the link. Pages are prerendered, accessible, and work without JavaScript for content (interactivity requires JS).

## Core calculators

- [Basic Calculator](https://calcu.lol/en/basic-calculator) - Add, subtract, multiply, divide with visual diagrams.
- [Rule of Three](https://calcu.lol/en/rule-of-three) - Solve direct and inverse proportions visually.
- [Percentage Calculator](https://calcu.lol/en/percentage) - Percent of, what percent, and percent change with grids, pies, and bars.
- [Trigonometry](https://calcu.lol/en/trigonometry) - sin, cos, tan and inverses on an interactive unit circle.
- [Triangle Solver](https://calcu.lol/en/triangle-solver) - Solve triangles from sides and angles (SSS/SAS/ASA/AAS/SSA).
- [Circle Calculator](https://calcu.lol/en/circle-calculator) - Radius, diameter, circumference, and area from any single value.
- [Unit Converter](https://calcu.lol/en/unit-converter) - Length, mass, temperature, volume, speed, time, data, area.
- [Fractions](https://calcu.lol/en/fractions) - Add, subtract, multiply, and divide fractions with simplification.
- [GCD / LCM](https://calcu.lol/en/gcd-lcm) - Greatest common divisor and least common multiple with factor breakdowns.
- [Exponents and Roots](https://calcu.lol/en/exponents-roots) - Powers and nth roots for real numbers.
- [Logarithms](https://calcu.lol/en/logarithms) - Solve for result, argument, or base; supports natural log.
- [Statistics](https://calcu.lol/en/statistics) - Mean, median, mode, variance, quartiles, dot and box plots.

## Everyday and finance

- [Tip Calculator](https://calcu.lol/en/tip-calculator) - Bill totals and per-person amounts.
- [Discount Calculator](https://calcu.lol/en/discount-calculator) - Sale price and savings.
- [BMI Calculator](https://calcu.lol/en/bmi-calculator) - Body mass index from height and weight.
- [Age Calculator](https://calcu.lol/en/age-calculator) - Exact age in years, months, days.
- [Compound Interest](https://calcu.lol/en/compound-interest) - Growth over time with contributions.
- [Loan Calculator](https://calcu.lol/en/loan-calculator) - Monthly payment, interest, amortization.
- [Speed, Distance, Time](https://calcu.lol/en/speed-distance-time) - Solve for any of the three.

## Geometry and science

- [Pythagorean Theorem](https://calcu.lol/en/pythagorean-theorem) - Solve for any side of a right triangle.
- [Area and Perimeter](https://calcu.lol/en/area-perimeter) - For common 2D shapes.
- [Volume Calculator](https://calcu.lol/en/volume-calculator) - For common 3D shapes.
- [Ohm's Law](https://calcu.lol/en/ohms-law) - Voltage, current, resistance, power.
- [Kinematics](https://calcu.lol/en/kinematics) - Motion under constant acceleration.

## Common unit converters

- [cm to inches](https://calcu.lol/en/cm-to-inches), [inches to cm](https://calcu.lol/en/inches-to-cm)
- [km to miles](https://calcu.lol/en/km-to-miles), [miles to km](https://calcu.lol/en/miles-to-km)
- [kg to lbs](https://calcu.lol/en/kg-to-lbs), [lbs to kg](https://calcu.lol/en/lbs-to-kg)
- [Celsius to Fahrenheit](https://calcu.lol/en/celsius-to-fahrenheit), [Fahrenheit to Celsius](https://calcu.lol/en/fahrenheit-to-celsius)
- [liters to gallons](https://calcu.lol/en/liters-to-gallons), [gallons to liters](https://calcu.lol/en/gallons-to-liters)
- [GB to MB](https://calcu.lol/en/gb-to-mb), [MB to GB](https://calcu.lol/en/mb-to-gb)

## Resources

- [Sitemap](https://calcu.lol/sitemap.xml) - Complete list of all calculator pages across all locales.
- [robots.txt](https://calcu.lol/robots.txt) - Crawling policy. AI crawlers are explicitly allowed.
- [API catalog](https://calcu.lol/.well-known/api-catalog) - RFC 9727 discovery document for the public server catalog API.
- [API documentation](https://calcu.lol/api.md) - Human-readable documentation for the public API.
- [OpenAPI description](https://calcu.lol/api/openapi.json) - Machine-readable OpenAPI 3.1 description.
- [Agent Skills](https://calcu.lol/.well-known/agent-skills/index.json) - Discovery index for reusable agent instructions.

## Localized homepages

- [English](https://calcu.lol/en)
- [Spanish](https://calcu.lol/es)
- [Chinese](https://calcu.lol/zh)
- [Arabic](https://calcu.lol/ar)
- [Portuguese](https://calcu.lol/pt)
- [Japanese](https://calcu.lol/ja)
- [French](https://calcu.lol/fr)
- [German](https://calcu.lol/de)