Conversion Calculator

Convert units quickly and accurately across length, mass, temperature, volume, area, speed, time, and digital data.

Enter a number to convert.

Quick conversions

Useful nearby values for the units you selected.

Common conversion reference

Frequently used conversion facts you can check at a glance.

Length

  • 12 inches = 1 foot
  • 3 feet = 1 yard
  • 1 mile = 5,280 feet
  • 1 kilometer ≈ 0.621 miles
  • 1 meter ≈ 3.281 feet
  • 1 inch = 2.54 centimeters

Weight / Mass

  • 16 ounces = 1 pound
  • 2,000 pounds = 1 US ton
  • 1 kilogram ≈ 2.205 pounds
  • 1 pound ≈ 0.454 kilograms
  • 1 ounce ≈ 28.35 grams

Volume

  • 3 teaspoons = 1 tablespoon
  • 16 tablespoons = 1 US cup
  • 2 cups = 1 US pint
  • 2 pints = 1 US quart
  • 4 quarts = 1 US gallon
  • 1 liter ≈ 0.264 US gallons

Temperature

  • 0°C = 32°F
  • 100°C = 212°F
  • °F = (°C × 9/5) + 32
  • °C = (°F − 32) × 5/9
  • Kelvin = °C + 273.15

How this conversion works

Conversion results are mathematical estimates. Standard unit factors are used; rounding may affect the final displayed digits.

How to use the conversion calculator

Choose a category, type a number in the From box, and pick the units you are converting from and to. The answer updates as you type. Use the ⇄ button to swap the two units, and Copy result to copy the answer.

The calculator covers eight categories: length, weight and mass, temperature, volume, area, speed, time, and digital data.

Everyday conversions to remember

  • 1 inch = 2.54 centimeters (exactly)
  • 1 foot = 30.48 centimeters
  • 1 mile = 1.609 kilometers, so 5 km is about 3.11 miles
  • 1 kilogram = 2.205 pounds, and 1 pound = 0.4536 kilograms
  • 1 US gallon = 3.785 liters
  • 1 US cup = about 237 milliliters
  • 1 US tablespoon = 3 teaspoons = about 14.8 milliliters

How temperature conversion works

Temperature is different from other units, because the scales don’t start at the same zero. You can’t just multiply:

  • °C to °F: multiply by 9/5, then add 32
  • °F to °C: subtract 32, then multiply by 5/9
  • °C to Kelvin: add 273.15

Example: 100°F is (100 − 32) × 5 ÷ 9 = 37.8°C. A quick way to estimate °C to °F in your head is to double the number and add 30. So 20°C is roughly 70°F (the exact answer is 68°F).

Metric vs. US customary units

Most of the world uses the metric system, which is based on multiples of 10. The United States still uses customary units, such as inches, pounds, and gallons, in daily life. If you travel, shop online from another country, or follow a recipe written somewhere else, a quick conversion saves a lot of guessing.

Be careful with US vs. UK units. A US gallon (3.785 L) is smaller than a UK imperial gallon (4.546 L), and US cups and pints are also different from British ones. The volume units in this calculator are US units.

Digital data units

Storage is usually counted in steps of 1,000 (a kilobyte is 1,000 bytes), while some computers count in steps of 1,024. That’s why a new “1 TB” drive can show up as about 931 GB on your computer.

Common questions

How accurate are the conversions?

The calculator uses standard conversion factors, many of which are exact by definition, such as 1 inch = 2.54 cm and 1 pound = 0.45359237 kg. Results are rounded for display.

Why are recipe cups confusing?

Cup sizes vary by country. A US cup is about 237 mL, while a metric cup, used in Australia and elsewhere, is 250 mL.

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