Unit Converter

Convert length, weight, volume, temperature, area, and speed instantly

Value

Result

—

Common Unit Conversions

Here are the most frequently searched unit conversions across all categories:

Length

From	To	Multiply by
Inches	Centimeters	2.54
Feet	Meters	0.3048
Miles	Kilometers	1.60934
Yards	Meters	0.9144

Weight

From	To	Multiply by
Pounds	Kilograms	0.453592
Ounces	Grams	28.3495
Stones	Kilograms	6.35029
Tons (US)	Kilograms	907.185

Temperature

Conversion	Formula
Celsius → Fahrenheit	(°C × 9/5) + 32
Fahrenheit → Celsius	(°F − 32) × 5/9
Celsius → Kelvin	°C + 273.15
Kelvin → Celsius	K − 273.15

Metric vs Imperial: Which System?

Most of the world uses the metric system (SI units) — meters, kilograms, liters. The United States, Liberia, and Myanmar are the only countries that haven't fully adopted the metric system and still use imperial units (feet, pounds, gallons) in everyday life.

The metric system is based entirely on powers of 10, making conversions within the system trivial (1 kilometer = 1,000 meters, 1 kilogram = 1,000 grams). Imperial conversions are historically derived and less logical — 1 mile = 5,280 feet, 1 gallon = 128 fluid ounces.

Frequently Asked Questions

How accurate are the conversions?

All conversions use internationally defined exact factors (e.g., 1 inch = 2.54 cm exactly). Results are displayed to up to 8 significant figures. For scientific work, be aware of floating-point precision limits in JavaScript.

Why does temperature conversion work differently?

Most unit conversions are simple multiplication (linear). Temperature scales use both multiplication and addition because they have different zero points — 0°C is not the same as 0°F. Celsius zero is water's freezing point; Fahrenheit zero is a historical brine-freezing point.

What is a "stone" in weight?

A stone is a unit of weight used in the UK and Ireland equal to 14 pounds or 6.35 kilograms. It is commonly used for measuring body weight — for example, "11 stone 4" means 11 × 14 + 4 = 158 pounds (71.7 kg).