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Converters

The Converters translate between metric and imperial units for the six quantities that come up most: length, area, volume, weight, temperature and speed. Every converter uses exact conversion factors (not rounded approximations) and returns the result instantly, with a reference table of the common equivalents.

Whether you are reading a recipe in cups, a building plan in feet, or a car brochure in MPG, these tools give you the precise number without remembering whether a US gallon is 3.785 or 4.546 litres.

Length Converter Convert length between metric and imperial units: mm, cm, meters, km, inches, feet, yards and miles. Area Converter Convert area between square meters, square feet, square yards, acres and hectares. Volume Converter Convert volume between liters, milliliters, cubic meters, gallons, cups, pints and fluid ounces. Weight Converter Convert weight between kilograms, grams, pounds, ounces, stones, metric tonnes and US tons. Temperature Converter Convert temperature between Celsius, Fahrenheit and Kelvin with exact formulas. Speed Converter Convert speed between km/h, mph, m/s, ft/s and knots.

Frequently asked questions

Are the conversion factors exact?

Yes. Length, area, volume, weight and speed use defined exact factors (for example 1 inch = 25.4 mm exactly). Temperature uses the exact Celsius/Fahrenheit formulas.

How do I convert Celsius to Fahrenheit?

F = C × 9 ÷ 5 + 32. The Temperature Converter handles C↔F and Kelvin in both directions.

What is the difference between a US and an imperial gallon?

A US gallon is 3.785 litres; an imperial (UK) gallon is 4.546 litres. The Volume Converter lists both so you always pick the right one.

How do I convert square feet to square metres?

Multiply by 0.092903: 100 ft² = 9.29 m². The Area Converter handles all common area units including acres and hectares.

Can I convert speed between km/h and mph?

Yes — 1 km/h = 0.621371 mph. The Speed Converter also handles m/s and knots for running, cycling and aviation.