Unit Converter – Length, Weight, Temperature & More

This free unit converter turns one unit into another across five categories — length, weight, temperature, volume, and speed — with an accurate result the moment you type. Pick a category, choose your two units, and read the conversion instantly, along with a plain-language line showing the full equation. It is made for everyday needs and technical ones alike: cooks converting cups to milliliters, travelers switching miles to kilometers, students checking physics answers, and DIYers moving between metric and imperial. No sign-up, no app, and nothing leaves your browser. Pick a category above and start converting.

What does this tool do?

It converts a value from one unit to another within the same category and shows the result and the equation. The five categories and their units:

• Length — mm, cm, m, km, inch, foot, yard, mile.
• Weight — mg, g, kg, metric ton, ounce, pound, stone.
• Temperature — Celsius, Fahrenheit, Kelvin.
• Volume — ml, liter, cubic meter, teaspoon, tablespoon, fluid ounce, cup, pint, quart, gallon (US).
• Speed — m/s, km/h, mph, ft/s, knot.

Why use this tool?

Unit conversions come up constantly and are easy to get wrong under pressure — a recipe in metric, a distance in miles, a weight limit in kilograms. Doing the math by hand invites mistakes, especially with temperature, which does not scale by a simple factor. This converter applies the correct method every time and updates live, so you can check a value or compare units in seconds without a calculator.

How the tool works

For length, weight, volume, and speed, each unit has a fixed factor relative to a base unit. The tool converts your value to that base unit, then to the target unit — a two-step method that keeps results accurate across any pair.

• Length uses meters as the base (1 foot = 0.3048 m, 1 mile = 1609.344 m).
• Weight uses kilograms (1 pound = 0.45359237 kg).
• Volume uses liters; US customary units are used for cups, pints, and gallons.
• Speed uses meters per second (1 mph = 0.44704 m/s).
• Temperature is different — it uses formulas, not a factor. Celsius to Fahrenheit is (°C × 9/5) + 32; Celsius to Kelvin is °C + 273.15. The tool converts to Celsius first, then to the target scale.

How to use the tool

Practical examples

Common use cases

• Cooking & baking: switching recipes between metric and US measures.
• Travel: distances, speeds, and temperatures abroad.
• Students: checking physics and chemistry answers.
• Trades & DIY: measurements and material weights in either system.
• Fitness: converting weights between pounds and kilograms.

Tips & best practices

• Note that volume units here are US customary — a US cup (about 237 ml) differs from a metric cup (250 ml).
• For temperature, remember it is not proportional: 0 °C is not "zero" on other scales, it is 32 °F and 273.15 K.
• Use the swap button to check a conversion both ways at a glance.
• For very large or very small numbers, the result keeps up to six decimals for precision.