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About This Calculator
Unit conversion is one of the most common mathematical tasks in science, engineering, cooking, and everyday life. This comprehensive calculator handles conversions across length, weight, volume, temperature, speed, area, and many other categories. It removes the need to memorize hundreds of conversion factors by providing instant, accurate results between metric and imperial systems.
Quick Tips
- 1 Multiply miles by 1.609 for kilometers and pounds by 0.4536 for kilograms.
- 2 One fluid ounce equals exactly 29.5735 milliliters in the US system.
- 3 Temperature conversion: multiply Celsius by 1.8 then add 32 for Fahrenheit.
Example Calculation
Convert 185 centimeters to feet and inches.
185 cm = 6 feet 0.83 inches (approx 6'1") | Also: 1.85 m = 72.83 inches
How Unit Conversion Works
Unit conversion multiplies or divides by a conversion factor. To convert 100 meters to feet, multiply by 3.28084 (1 meter = 3.28084 feet). Temperature conversions use formulas rather than simple multiplication: F = C x 9/5 + 32.
Length Conversions
Key conversions: 1 mile = 1.60934 km = 5,280 feet. 1 meter = 3.28084 feet = 39.3701 inches. 1 inch = 2.54 cm exactly. 1 yard = 3 feet = 0.9144 meters. These are the most commonly needed length conversions.
Weight and Mass Conversions
Key conversions: 1 kilogram = 2.20462 pounds. 1 pound = 16 ounces = 453.592 grams. 1 ounce = 28.3495 grams. The kilogram is the SI base unit of mass, while pounds and ounces are US customary units.
Volume and Temperature Conversions
Volume: 1 gallon = 3.78541 liters = 16 cups. 1 liter = 1,000 mL = 0.264172 gallons. Temperature: C = (F - 32) x 5/9. K = C + 273.15. Water freezes at 0°C / 32°F / 273.15K and boils at 100°C / 212°F / 373.15K.
Frequently Asked Questions
You can only convert between units of the same type. Length to length, weight to weight, temperature to temperature, and volume to volume. Converting meters to kilograms, for example, is not meaningful.
The metric system (SI) was developed in France in the 1790s for scientific consistency. The US customary system evolved from English units. Most countries have adopted metric, but the US, Liberia, and Myanmar still primarily use customary units.
Multiply the Celsius temperature by 9/5 (or 1.8) and add 32. For example, 25°C x 1.8 + 32 = 77°F. For a quick estimate, double the Celsius value and add 30.
Kelvin is the SI unit of temperature used in science. It starts at absolute zero (the coldest possible temperature). 0 K = -273.15°C = -459.67°F. Kelvin is essential for gas laws, thermodynamics, and astrophysics.