Instantly convert between all common units across 5 categories: Length, Weight, Temperature, Volume, and Speed. Click any result to copy it.
Unit conversion is essential in science, engineering, cooking, fitness, international trade, and daily life. This converter handles the most common unit categories with precision up to 10 significant figures.
The metric system is based on the metre (m). The imperial/US system uses inches, feet, yards, and miles. The international inch is exactly 25.4mm. One foot = 12 inches. One yard = 3 feet. One mile = 1,609.344 metres.
The gram (g) is the base unit in the metric system (though the kilogram is the SI base unit). The imperial system uses ounces (oz), pounds (lb), and stones (st). One pound = 453.59237 grams. One ounce = 28.3495 grams.
Celsius (°C) is the standard in most countries. Fahrenheit (°F) is used primarily in the US. Kelvin (K) is the SI unit used in science. Formulas: °F = °C × 9/5 + 32. K = °C + 273.15.
The litre (L) is the standard metric unit for liquid volume. US and Imperial cups/pints/gallons differ — an Imperial gallon (4.546L) is larger than a US gallon (3.785L). US cups (236.6ml) also differ from metric cups (250ml).
Metres per second (m/s) is the SI speed unit. Kilometres per hour (km/h) is used on roads in most countries. Miles per hour (mph) is used in the US and UK. One knot = one nautical mile per hour = 1.852 km/h, used in aviation and maritime navigation.