Unit Converter

Supported Unit Categories

Length Conversions

Weight Conversions

Temperature Conversions

Temperature conversions use the following formulas:

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

Common Conversion Examples

• Height: 6 feet = 1.83 meters
• Distance: 1 mile = 1.61 kilometers
• Weight: 1 pound = 0.45 kilograms
• Temperature: 32°F = 0°C = 273.15K
• Cooking: 1 cup = 240 milliliters

Measurement Systems

• Metric System: Used worldwide, based on powers of 10
• Imperial System: Used primarily in the US and UK
• SI Units: International standard for scientific measurements
• Customary Units: Traditional units still used in some regions

Practical Applications

• Travel: Convert distances and temperatures for international travel
• Cooking: Convert recipe measurements between systems
• Shopping: Compare product sizes and weights
• Science: Convert between different measurement units
• Construction: Convert building measurements and materials
• Health: Convert body measurements and medication dosages

How Unit Conversion Works

Almost every unit conversion follows the same simple principle: each unit is defined as a multiple of a single base unit within its category. For length the base unit is the metre, for mass it is the kilogram, and for volume it is the litre. To convert between any two units, this tool first converts your input value into the base unit, then divides by the target unit's factor. For example, to convert 5 miles to kilometres, it multiplies 5 by 1,609.34 to get 8,046.7 metres, then divides by 1,000 to get 8.05 km. Because every unit shares a common reference point, the same two-step method works across thousands of unit pairs without special cases.

Temperature is the one exception. Celsius, Fahrenheit, and Kelvin do not share a common zero point, so they require dedicated formulas rather than a simple multiplication factor. That is why converting 0°C to Fahrenheit gives 32°F rather than 0 — the scales are offset as well as differently spaced.

Worked Examples

• Length: Convert 100 cm to inches → 100 × 0.01 = 1 m, then 1 ÷ 0.0254 = 39.37 inches.
• Weight: Convert 75 kg to pounds → 75 ÷ 0.453592 = 165.3 lb.
• Temperature: Convert 98.6°F to Celsius → (98.6 − 32) × 5/9 = 37°C (normal body temperature).
• Speed for travel: A 60 mph speed limit equals 60 × 1.609 = 96.6 km/h.

Metric vs Imperial: Why Two Systems Exist

The metric system was designed in late-18th-century France to be decimal and universal — every unit is a power of ten of the next, which makes mental arithmetic straightforward. It is now the official system in almost every country and the standard for all scientific work. The imperial system descends from older English units based on everyday references such as the foot and the pound, and it remains in common use in the United States and, partially, in the United Kingdom. Mixing the two has caused famous engineering failures, including the loss of NASA's Mars Climate Orbiter in 1999, when one team used metric units and another used imperial — a costly reminder to always confirm which system a measurement uses.

Common Conversion Mistakes to Avoid

• Confusing weight and mass: Kilograms measure mass while pounds are often used for weight; for everyday purposes the conversion holds, but they are not physically identical.
• US vs Imperial gallons: A US gallon is 3.785 litres while an imperial (UK) gallon is 4.546 litres — always check which one a recipe or fuel figure refers to.
• Rounding too early: Round only your final answer, not intermediate steps, to avoid compounding small errors.
• Temperature offsets: Remember that temperature scales need their offset applied, so you cannot simply multiply by a factor.