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Converters

Transform data between formats, units, and encodings instantly. Convert temperatures, lengths, weights, colors, numbers between bases, and encode/decode text.

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Unit Converter

Convert temperature, length, weight, and volume

Complete guide to conversions

Unit conversions are essential in our globalized world where different measurement systems coexist. Whether you're cooking with an international recipe, planning a trip, or working on a technical project, mastering conversions saves time and avoids costly errors.

Measurement systems around the world

Two measurement systems dominate worldwide:

  • The metric system (SI): used by most countries, based on multiples of 10 (meter, gram, liter)
  • The imperial system: used primarily in the United States (foot, pound, gallon)

The metric system has been officially adopted by most countries since the 19th century due to its simplicity. Conversions are intuitive: 1 km = 1000 m, 1 kg = 1000 g. The imperial system, inherited from the British Empire, uses less regular conversion factors (12 inches = 1 foot, 16 ounces = 1 pound).

Temperature conversions

Temperature is measured primarily with three scales:

  • Celsius (°C): used worldwide, where 0° = water's freezing point and 100° = boiling point
  • Fahrenheit (°F): used in the United States, where 32° = freezing and 212° = boiling
  • Kelvin (K): absolute scientific scale, where 0 K = absolute zero (-273.15°C)

Conversion formulas:

  • °F = (°C × 9/5) + 32
  • °C = (°F - 32) × 5/9
  • K = °C + 273.15

Tip: 28°C ≈ 82°F is a good summer temperature, while -40° is identical in Celsius and Fahrenheit.

Length conversions

Lengths range from microscopic to cosmic. Here are the most useful conversions:

Metric:

  • 1 kilometer (km) = 1000 meters (m)
  • 1 meter = 100 centimeters (cm)
  • 1 centimeter = 10 millimeters (mm)

Imperial:

  • 1 mile = 1.609 km
  • 1 yard = 0.914 m
  • 1 foot = 30.48 cm = 12 inches
  • 1 inch = 2.54 cm

To remember: your thumb measures about 2.5 cm, a normal step is about 75 cm, and a football field is about 100 m.

Weight and mass conversions

Weight and mass, although technically different, are often used interchangeably in daily life:

Metric:

  • 1 metric ton = 1000 kilograms (kg)
  • 1 kilogram = 1000 grams (g)
  • 1 gram = 1000 milligrams (mg)

Imperial:

  • 1 pound (lb) = 453.6 g ≈ 0.45 kg
  • 1 ounce (oz) = 28.35 g
  • 1 stone = 14 pounds = 6.35 kg (used in the UK)

For cooking: 1 cup of flour ≈ 125 g, 1 cup of sugar ≈ 200 g. These equivalents vary depending on the ingredient's density.

Volume conversions

Volume measures the space occupied by a liquid or solid:

Metric:

  • 1 liter (L) = 1000 milliliters (mL) = 1 dm³
  • 1 cubic meter (m³) = 1000 liters

Imperial (note US/UK differences):

  • 1 US gallon = 3.785 L
  • 1 UK gallon = 4.546 L
  • 1 US quart = 0.946 L
  • 1 US pint = 0.473 L
  • 1 US cup = 236.6 mL ≈ 240 mL
  • 1 tablespoon = 15 mL
  • 1 teaspoon = 5 mL

In cooking, American and British measurements differ—be careful with international recipes.

Encoding and data formats

Beyond physical units, our tools also convert data formats:

  • Base64: encodes binary data into ASCII text, useful for transmitting files in emails or URLs
  • URL encoding: transforms special characters for URLs (%20 for space)
  • HTML entities: converts special characters for web display (& for &)

Number base conversions:

  • Binary (base 2): 0 and 1, used by computers
  • Octal (base 8): 0-7, used in Unix programming
  • Decimal (base 10): 0-9, our everyday system
  • Hexadecimal (base 16): 0-9 and A-F, used for web colors and memory addresses

Precision and rounding

Conversion precision depends on context:

  • Daily use: 1-2 decimals are sufficient (1 mile ≈ 1.6 km)
  • Cooking: round to practical measures (240 mL rather than 236.59 mL)
  • Engineering: several decimals may be necessary
  • Sciences: precision depends on measurement uncertainty

Beware of cumulative rounding errors. For critical calculations, keep more decimals during intermediate calculations and round only the final result.

Our calculators use high internal precision and display appropriately rounded results.

Quick conversion tips

Some useful approximations for quick estimates:

Length:

  • km → miles: divide by 1.6 (or multiply by 0.6)
  • cm → inches: divide by 2.5
  • 1 foot ≈ 30 cm

Weight:

  • kg → pounds: multiply by 2.2
  • pounds → kg: divide by 2.2

Temperature:

  • To roughly convert °C to °F: double and add 30
  • 20°C ≈ 68°F (comfortable), 30°C ≈ 86°F (hot)

Volume:

  • 1 liter ≈ 4 cups
  • 1 US gallon ≈ 4 liters

These shortcuts are perfect for quick estimates; use our tools for precise conversions.