Unit Converter

Converting between metric and imperial systems requires using standardized conversion factors. For example, to convert meters to feet, multiply by 3.28084, so 5 meters equals 16.4042 feet (5 × 3.28084). To convert pounds to kilograms, multiply by 0.453592, meaning 150 pounds equals 67.9 kilograms (150 × 0.453592). Our converter handles all common conversions automatically using internationally recognized conversion factors. Simply enter your value, select your starting unit and desired unit, and the calculator performs the conversion instantly with precise results to 10 decimal places.

To convert Celsius to Fahrenheit, multiply the Celsius temperature by 9/5 (or 1.8), then add 32. The formula is: °F = (°C × 9/5) + 32. For example, 20°C equals 68°F because (20 × 1.8) + 32 = 68. To convert Fahrenheit to Celsius, subtract 32 first, then multiply by 5/9: °C = (°F - 32) × 5/9. So 68°F becomes 20°C: (68 - 32) × 5/9 = 20. Temperature conversions don't use simple multiplication factors like other units because the scales have different zero points and degree sizes.

One meter equals exactly 3.28084 feet, or approximately 3 feet and 3.37 inches. This conversion is crucial for international construction projects, athletic measurements, and scientific work where metric and imperial systems intersect. For example, a 100-meter sprint equals 328.084 feet, while a 6-foot-tall person is 1.83 meters tall. Understanding this conversion helps when reading European product specifications, international building plans, or Olympic records. Our square footage calculator also uses these conversions to help with room measurements in different unit systems.

Mass measures the amount of matter in an object (kilograms, grams, pounds), while weight is the force of gravity acting on that mass (newtons, pounds-force). On Earth, weight and mass are proportional, so we often use them interchangeably in everyday conversations. A 70-kilogram person has a mass of 70 kg everywhere in the universe, but their weight varies with gravity: 686.7 newtons on Earth, 113.4 newtons on the Moon. For practical purposes, when converting between pounds and kilograms, you're technically converting mass units, and the relationship is: 1 pound-mass = 0.453592 kilograms.

To convert kilograms to pounds, multiply the kilogram value by 2.20462. For example, 70 kilograms equals 154.32 pounds (70 × 2.20462 = 154.324). To convert pounds to kilograms, divide by 2.20462 or multiply by 0.453592. So 150 pounds equals 68.04 kilograms (150 ÷ 2.20462 = 68.039). This conversion is essential when traveling internationally, reading medical records from different countries, or following fitness programs that use different measurement systems. A quick approximation is that 1 kg ≈ 2.2 lbs, useful for mental calculations. For percentage-based weight changes, check our percentage calculator.

Many conversion factors are irrational numbers or long decimals, which is why precise conversions show many decimal places. For example, 1 inch equals exactly 2.54 centimeters, but 1 foot equals 30.48 centimeters, and 1 meter equals 3.280839895... feet (continuing indefinitely). Our calculator displays results to 10 decimal places for maximum accuracy, but you should round to an appropriate precision for your use case. For construction, round to the nearest 1/16 inch; for scientific work, use as many significant figures as your measurements warrant. The full precision prevents rounding errors when doing multiple conversions. For time-related unit calculations, our time calculator provides similar precision for hours, minutes, and seconds.

One US gallon equals 3.78541 liters, while one imperial (UK) gallon equals 4.54609 liters - be sure to know which gallon type you're converting. To convert US gallons to liters, multiply by 3.78541: 10 US gallons = 37.8541 liters. To convert liters to US gallons, divide by 3.78541: 40 liters = 10.57 US gallons. This conversion is essential when comparing fuel economy (MPG vs. L/100km), cooking with international recipes, or understanding container capacities. Our converter defaults to US gallons, which are most common in the United States.

No, you cannot directly convert between different measurement types (length, weight, volume, temperature) because they measure fundamentally different physical properties. Length measures distance, volume measures space capacity, and weight measures mass. However, you can use mathematical relationships: area equals length × width, and volume equals length × width × height. For example, a 2-meter by 3-meter rectangle has 6 square meters of area, but you cannot convert "6 square meters" to kilograms without additional information. Use our square footage calculator for area calculations from length measurements.

Online unit converters using official conversion factors are extremely accurate, typically to 10+ decimal places. Our calculator uses conversion factors defined by international standards organizations like NIST (National Institute of Standards and Technology) and BIPM (International Bureau of Weights and Measures). For example, the meter is defined precisely relative to the speed of light, making conversions mathematically exact. However, real-world measurements introduce uncertainty - if you measure a room as "12 feet" with a tape measure, your measurement might be 12 ± 0.1 feet, so reporting converted values to 0.0001 meters would be false precision.

Kelvin is the absolute temperature scale used primarily in scientific and engineering applications, especially thermodynamics, chemistry, and physics calculations. Unlike Celsius and Fahrenheit, Kelvin starts at absolute zero (the coldest possible temperature), making it essential for gas laws, entropy calculations, and astronomical measurements. To convert Celsius to Kelvin, simply add 273.15: room temperature of 20°C equals 293.15 K. Scientists prefer Kelvin because temperature ratios work correctly: 400 K is truly twice as hot as 200 K, while 400°C is not twice as hot as 200°C. For everyday weather and cooking, Celsius or Fahrenheit remain more practical.