No accounts, no uploads, no server

Convert, calculate, generate.

A converter, a calculator and a generator are the same thing underneath: a function. One engine runs all of them, in your browser, and every number it prints can be traced to a published source.

Try

Convert

15 tools

Any two units of a dimension, composed through a base chosen for numerical stability. Adding the hundredth converter is one file of data, not one more component.

km → mi · °C → °F · kg → lb

Calculate

3 tools

Formulas with several inputs and named results, each carrying the source it was taken from and the values it has to reproduce.

BMI · percentages · interest

Generate

2 tools

Anything derivable from its input: CSS, colours, identifiers, text. Deterministic generators are checked against the specification they implement.

gradients · palettes · passwords

Everything built so far 20

The catalogue grows one tool at a time, and every one is written by hand with its own formula, source and worked examples. Nothing here was mass generated to fill a sitemap.

converterLength

Kilometers to Miles

Convert kilometers to miles instantly in your browser. One mile is exactly 1.609344 kilometers, the factor fixed by the international yard and pound agreement.

converterLength

Miles to Kilometers

Convert miles to kilometers in your browser. One mile is exactly 1.609344 kilometers, so the answer is a fixed ratio rather than an approximation.

converterLength

Meters to Feet

Convert meters to feet instantly. A foot is exactly 0.3048 meters, so the conversion is a definition rather than a measurement.

converterLength

Centimeters to Inches

Convert centimeters to inches in your browser. An inch is exactly 25.4 millimeters, fixed by international agreement in 1959.

converterMass

Kilograms to Pounds

Convert kilograms to pounds in your browser. One pound is exactly 0.45359237 kilograms, the value fixed by the international yard and pound agreement.

converterMass

Grams to Ounces

Convert grams to ounces for recipes and postage. One avoirdupois ounce is a sixteenth of a pound, which works out at 28.349523125 grams exactly.

converterTemperature

Celsius to Fahrenheit

Convert Celsius to Fahrenheit in your browser. Temperature is an offset scale, not a simple multiple, so 0 °C is 32 °F rather than zero.

converterTemperature

Fahrenheit to Celsius

Convert Fahrenheit to Celsius using the exact relation published by NIST, computed in your browser with no detour through kelvin.

generatorCSS

CSS Gradient Generator

Build a CSS gradient and copy the exact declaration. Angles follow the CSS specification, where 0deg points up and angles turn clockwise.

calculatorHealth

BMI Calculator

Work out body mass index from height and weight using the WHO definition, with the two thresholds the WHO actually publishes for adults.

transformerImage

PNG to JPG

Convert PNG images to JPG in your browser. The file never leaves your device — there is no upload, no queue and no copy left on a server.

transformerImage

PNG to WebP

Convert PNG images to WebP without losing transparency. Everything runs in your browser, so nothing is uploaded and nothing is stored.

transformerImage

JPG to WebP

Convert JPG photographs to WebP to cut page weight. The conversion happens in your browser, with no upload and no account.

transformerImage

JPG to PNG

Convert JPG to PNG in your browser. Useful before editing, because every later save is lossless — though it cannot restore what JPEG already discarded.

transformerImage

WebP to PNG

Convert WebP images to PNG for software that will not open WebP. Runs in your browser, keeps transparency, uploads nothing.

calculatorColor

HEX to RGB

Convert a hex colour to its red, green and blue channels, including the shorthand and alpha forms defined by the CSS specification.

converterSpeed

km/h to mph

Convert kilometers per hour to miles per hour. The ratio is the same exact 1.609344 that relates the two distance units, because an hour is an hour on both sides.

converterVolume

Liters to Gallons

Convert liters to US or imperial gallons. The two gallons differ by about twenty percent, so this converter keeps them as separate units rather than guessing.

generatorSecurity

Password Generator

Generate a random password in your browser, with a length range taken from the NIST digital identity guidelines. Nothing is transmitted and nothing is stored.

calculatorMath

Percentage Calculator

Work out a percentage of a number, the result of adding or removing it, and the percentage change between two values — all at once.

Where it is heading

These are the areas the engine already covers by design — each one needs its own written page before it appears above.

A tool that is wrong is worse than no tool

One bad factor costs the trust of everything else on the site, so a tool whose reference values do not reproduce is not built at all. The numbers come from NIST, W3C and the WHO — transcribed from the source, never produced by our own code.

See how the converters are verified