Unit Converter

Convert between meters, feet, inches, centimeters, kilometers, miles, yards, and more. Perfect for construction, travel, or everyday measurements. 1 inch = 2.54 cm, 1 mile = 1.609 km.

Convert kilograms to pounds, ounces to grams, and more. Essential for cooking, fitness, and shipping. 1 kg = 2.205 lbs, 1 oz = 28.35 g.

Convert Celsius to Fahrenheit, Kelvin, and more. Use the formula °F = °C × 1.8 + 32 for quick conversions. Water freezes at 0°C (32°F) and boils at 100°C (212°F).

Convert liters to gallons, milliliters to cups, and more. Useful for cooking, fuel, and liquid measurements. 1 liter = 0.264 US gallons = 4.227 cups.

Easily switch between metric (SI) and imperial units. The metric system uses meters, kilograms, and liters, while imperial uses feet, pounds, and gallons. Our converter handles both systems seamlessly.

Convert bytes, kilobytes, megabytes, gigabytes, and terabytes. Understand the difference between binary (1 KB = 1024 bytes) and decimal (1 KB = 1000 bytes) standards.

Unit conversion works by multiplying a measured value by a conversion factor: a ratio equal to 1 that swaps one unit for another without changing the underlying quantity. For example, since 1 inch is defined as exactly 2.54 centimeters, the factor 2.54 cm per inch turns 10 inches into 25.4 cm. This method, often called dimensional analysis, is described in detail by Khan Academy and the U.S. National Institute of Standards and Technology (NIST). Because a conversion factor equals 1, you can chain several factors together (inches to feet to meters) and the units cancel algebraically, leaving only the target unit.

The core formula is Result = Value × Conversion Factor. To build the factor, express both units in terms of a shared base unit, then divide. For length, the SI base is the meter: 1 mile = 1609.34 m and 1 km = 1000 m, so 1 mile = 1.60934 km. Most categories use simple multiplication, but temperature is an exception because its scales have different zero points, so you apply °F = °C × 9/5 + 32 instead of a single factor. The International Bureau of Weights and Measures (BIPM) maintains the SI definitions, while Wolfram MathWorld and Encyclopaedia Britannica document the historical measurement systems these formulas connect.

Speed, energy, and pressure convert through defined base-unit factors. For speed, 1 knot equals exactly 1.852 km/h (one nautical mile per hour), and Mach 1 is roughly 343 m/s in air at 20°C. For energy, 1 kilowatt-hour equals 3,600,000 joules (3.6 MJ), 1 calorie equals 4.184 J, and 1 BTU is about 1055.06 J, per NIST. For pressure, 1 standard atmosphere equals 101,325 pascals, which is also 760 mmHg (760 torr) and about 14.696 psi. These physics-based conversions appear across engineering, meteorology, and lab work, and their exact factors are catalogued by NIST and Encyclopaedia Britannica.

Unit converters solve everyday and professional problems where two measurement systems collide. Travelers convert miles to kilometers and Fahrenheit to Celsius, cooks scale recipes between cups, milliliters, and grams, and shippers convert pounds to kilograms for customs. Engineers and scientists rely on precise conversions to prevent costly errors: NASA's 1999 Mars Climate Orbiter was lost because one team used imperial pound-force units while another expected metric newtons. Students preparing for physics and chemistry exams also use conversion practice from Khan Academy and Encyclopaedia Britannica to master dimensional analysis, a skill required across the sciences.

The most common conversion mistake is multiplying when you should divide, which inverts the result: to go from km to miles you divide by 1.60934, not multiply. A second error is treating temperature like other units and forgetting the +32 offset in °F = °C × 9/5 + 32. A third is confusing binary and decimal data sizes: 1 KB can mean 1024 bytes (binary) or 1000 bytes (decimal), a distinction the International Electrotechnical Commission clarifies with the term kibibyte. Also watch for identically named units that differ, such as US gallons (3.78541 L) versus UK gallons (4.54609 L). Always confirm which standard applies, as NIST and Wolfram MathWorld both emphasize.