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Measurement Converter

Free measurement converter to instantly convert between metric, imperial, and other measurement systems for length, weight, volume, temperature, and more.

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This measurement converter is perfect for international students studying in different countries, construction workers reading plans in different units, healthcare professionals converting patient measurements, scientists standardizing data, and home cooks adapting international recipes.

A measurement converter transforms values between different measurement systems—primarily metric (SI), imperial (US/UK), and other specialized systems. It ensures accurate conversions using standardized formulas and conversion factors.

The International System of Units used globally.

Base Units:

  • Length: meter (m)
  • Mass: kilogram (kg)
  • Volume: liter (L)
  • Temperature: Celsius (°C), Kelvin (K)
  • Time: second (s)

Prefixes:

  • kilo (k) = 1,000×
  • centi (c) = 0.01×
  • milli (m) = 0.001×

Traditional measurements used primarily in the United States.

Common Units:

  • Length: inch, foot, yard, mile
  • Mass: ounce, pound, ton
  • Volume: fluid ounce, cup, pint, quart, gallon
  • Temperature: Fahrenheit (°F)

Important differences:

  • US gallon ≠ Imperial gallon
  • US ton ≠ Imperial ton
  • US fluid ounce ≈ Imperial fluid ounce (slight difference)

Metric to Imperial:

  • 1 meter = 3.281 feet
  • 1 centimeter = 0.394 inches
  • 1 kilometer = 0.621 miles
  • 1 millimeter = 0.039 inches

Imperial to Metric:

  • 1 foot = 0.305 meters = 30.48 cm
  • 1 inch = 2.54 centimeters
  • 1 mile = 1.609 kilometers
  • 1 yard = 0.914 meters

Metric to Imperial:

  • 1 kilogram = 2.205 pounds
  • 1 gram = 0.035 ounces
  • 1 metric ton = 1.102 US tons

Imperial to Metric:

  • 1 pound = 0.454 kilograms = 454 grams
  • 1 ounce = 28.35 grams
  • 1 US ton = 0.907 metric tons

Metric to Imperial:

  • 1 liter = 0.264 US gallons
  • 1 liter = 4.227 cups (US)
  • 1 milliliter = 0.034 fluid ounces

Imperial to Metric:

  • 1 US gallon = 3.785 liters
  • 1 cup (US) = 237 milliliters
  • 1 fluid ounce (US) = 29.57 milliliters

Formulas:

  • Celsius to Fahrenheit: °F = (°C × 9/5) + 32
  • Fahrenheit to Celsius: °C = (°F - 32) × 5/9
  • Celsius to Kelvin: K = °C + 273.15

Common Conversions:

  • 0°C = 32°F (freezing point)
  • 100°C = 212°F (boiling point)
  • 37°C = 98.6°F (body temperature)
  • 20°C = 68°F (room temperature)

Convert recipe measurements between systems.

Examples:

  • 250 ml flour = 1.06 cups
  • 500 grams sugar = 2.5 cups
  • 180°C = 356°F (oven temperature)
  • 1 tablespoon = 15 ml

Read and convert building specifications.

Examples:

  • 2×4 lumber: 38mm × 89mm
  • 8-foot ceiling = 2.44 meters
  • 1/2 inch drywall = 12.7 mm
  • 16 inches on center = 40.64 cm

Convert body measurements and medication dosages.

Examples:

  • Height: 5’10” = 178 cm
  • Weight: 150 lbs = 68 kg
  • Medication: 500 mg = 0.5 grams
  • Blood pressure in mmHg

Understand distances and speeds in different countries.

Examples:

  • Speed limit: 65 mph = 105 km/h
  • Fuel economy: 30 mpg = 7.8 L/100km
  • Distance: 100 miles = 161 kilometers
  • Fuel: 50 liters = 13.2 gallons
MetricImperial
1 mm0.039 inches
1 cm0.394 inches
1 m3.281 feet
1 km0.621 miles
MetricImperial
1 g0.035 oz
100 g3.527 oz
1 kg2.205 lbs
1 tonne1.102 tons
MetricImperial (US)
1 ml0.034 fl oz
100 ml3.381 fl oz
1 L0.264 gallons
1 L4.227 cups
  • Recipe: 350°F = 177°C (oven setting)
  • Height: 6 feet = 183 cm (person)
  • Luggage: 23 kg = 50.7 lbs (airline limit)
  • Distance: 26.2 miles = 42.2 km (marathon)
  • Fuel: 40 liters = 10.6 gallons (gas tank)
  • Room: 12 ft × 15 ft = 3.66 m × 4.57 m
  • Package: 5 pounds = 2.27 kilograms
  • Liquid: 2 cups = 473 milliliters

Using Wrong Gallon Type: US gallon (3.785 L) ≠ Imperial gallon (4.546 L). Always specify which! UK recipes use Imperial gallons; US uses US gallons.

Temperature vs Temperature Difference: Converting 20°C to °F gives 68°F, but a 20°C temperature increase equals only 36°F increase. Use the right formula for values vs differences.

Confusing Weight and Mass: In everyday use, they’re interchangeable. Scientifically, mass (kg) is constant; weight (force) varies with gravity. For Earth conversions, treat as equivalent.

Mixing Precision Levels: Don’t convert rough measurements to excessive precision. “About 2 feet” becomes “approximately 61 cm,” not “60.96 cm exactly.”

Cooking Measurement Confusion: Cup sizes vary! US cup (237 ml) ≠ metric cup (250 ml) ≠ UK cup (284 ml). Know which system your recipe uses.

Area and Volume Complexity: Converting 1 m² to ft² isn’t 3.28 ft² (that’s length!). It’s 3.28² = 10.76 ft². Square the conversion for area; cube it for volume.

Select your measurement type (length, weight, volume), enter the metric value, and choose the imperial unit you want. The converter applies the correct formula instantly.

Why do we have different measurement systems?

Section titled “Why do we have different measurement systems?”

Historical development. Metric (1790s France) is decimal-based and logical. Imperial evolved from ancient Roman/British units. Most countries use metric; US primarily uses imperial.

Metric is easier (base-10, logical prefixes) and used globally for science. Imperial is familiar to US residents. Neither is objectively “better”—context matters.

Can I convert cooking measurements accurately?

Section titled “Can I convert cooking measurements accurately?”

Mostly yes, but ingredients vary in density. Volume conversions (cups to ml) are exact, but weight-to-volume (cups to grams) depends on the ingredient (flour vs sugar).

Very accurate. We use official conversion factors from NIST and ISO. Results show multiple decimal places, though practical use rarely needs more than 2-3.

What’s the easiest way to estimate conversions mentally?

Section titled “What’s the easiest way to estimate conversions mentally?”

For quick estimates: 1 kg ≈ 2 lbs, 1 meter ≈ 3 feet, 1 liter ≈ 1 quart (actually 0.95), 1 mile ≈ 1.6 km. For exact work, use the converter!