How the unit converter works
Unit Converter simplifies conversions between international metric (SI) and imperial measurement standards. Supported categories include length (millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles), weight (grams, kilograms, ounces, pounds, and stones), and temperature (Celsius, Fahrenheit, and Kelvin).
Conversions use precise standard conversion factors defined by international standards organizations (e.g., exactly 1 inch = 0.0254 meters, 1 pound = 0.45359237 kilograms). Temperature scales account for the varying zero-point offsets between absolute zero, the freezing point of water, and Fahrenheit's base scale.
Step-by-step instructions
- Select the measurement category: Length, Weight, or Temperature.
- Enter your starting numeric value.
- Select your source unit and target unit, then click Convert (or use Swap to reverse direction).
Key Conversion Formulas
• Celsius to Fahrenheit: °F = (°C × 9/5) + 32
• Fahrenheit to Celsius: °C = (°F - 32) × 5/9
• Celsius to Kelvin: K = °C + 273.15
• Imperial Length: 1 ft = 0.3048 m, 1 in = 0.0254 m
• Weight: 1 lb = 0.45359237 kgLength and weight units convert first to their respective base SI unit (meters or kilograms) before converting to the requested destination unit. Temperature scales use affine algebraic transformations to handle differing zero-points.
Practical example
Converting 68°F to Celsius: (68 - 32) × 5/9 = 36 × 5/9 = 20°C. Converting 150 lbs to kilograms: 150 × 0.45359237 = 68.038856 kg.
Frequently asked questions
Does the temperature converter allow values below absolute zero?
No. Temperatures below 0 Kelvin (-273.15°C or -459.67°F) are physically impossible and will trigger a validation alert.
Are the conversion factors exact or rounded?
We use exact legal standard definitions (such as 1 inch = exactly 2.54 cm and 1 lb = exactly 0.45359237 kg) before applying clean display formatting.
Can I convert quickly on a smartphone?
Yes, the interface is touch-optimized with a one-tap Swap button for rapid round-trip conversions on mobile screens.