Unit conversion is one of the most common everyday math tasks. Whether you are cooking, traveling, shipping a package, or reading international news — knowing how to convert between metric and imperial units is essential. This guide explains the most important conversions and how to do them instantly online.
Length / Distance Conversions
- 1 kilometer = 0.6214 miles
- 1 mile = 1.609 kilometers
- 1 meter = 3.281 feet
- 1 foot = 0.3048 meters
- 1 inch = 2.54 centimeters
- 1 centimeter = 0.394 inches
Weight / Mass Conversions
- 1 kilogram = 2.2046 pounds
- 1 pound = 0.4536 kilograms
- 1 gram = 0.0353 ounces
- 1 ounce = 28.35 grams
- 1 metric ton = 1,000 kg = 2,204.6 pounds
Temperature Conversions
Temperature conversion requires a formula, not just multiplication:
- Celsius → Fahrenheit: °F = (°C × 9/5) + 32
- Fahrenheit → Celsius: °C = (°F - 32) × 5/9
- Celsius → Kelvin: K = °C + 273.15
Common Temperature Reference Points
- 0°C = 32°F (water freezes)
- 20°C = 68°F (comfortable room temperature)
- 37°C = 98.6°F (average body temperature)
- 100°C = 212°F (water boils)
Volume Conversions
- 1 liter = 0.264 gallons (US)
- 1 gallon (US) = 3.785 liters
- 1 liter = 1,000 milliliters
- 1 cup (US) = 236.6 ml
- 1 tablespoon = 14.79 ml
Area Conversions
- 1 square meter = 10.764 square feet
- 1 acre = 4,047 square meters = 0.4047 hectares
- 1 hectare = 2.471 acres
Why the World Uses Two Different Systems
Most of the world uses the metric system (SI units), which is based on powers of 10. The United States (and a few other countries) still uses the imperial system. This is why international recipes, scientific data, and news reports often require conversion.
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Try Our Free Unit Converter →Frequently Asked Questions
What is the fastest way to convert Celsius to Fahrenheit mentally?
A quick mental shortcut: double the Celsius temperature and add 30. It is not perfectly accurate (exact formula: ×1.8 + 32) but good enough for everyday estimates. For example, 20°C: 20×2=40, +30=70°F (actual: 68°F).
Why does India use different units for land area?
India uses regional units like bigha, katha, and cent alongside the metric system for historical reasons. Our unit converter covers hectares, acres, and square meters — the most commonly used international area units.
Can I convert speed units like km/h to mph?
Yes! 1 km/h = 0.6214 mph. For example, 100 km/h = 62.14 mph. Our unit converter tool handles speed conversions among many other categories.
What units does the converter support?
Our tool covers length, weight, temperature, volume, area, speed, and digital storage units — all the most common conversion categories.