Unit converters
Two-way conversions based on the exact legal definitions: the math uses the official factor and only rounds when it shows you the result. Every converter includes a quick chart of common values.
5 calculators
Length
Metric to inches and back. Since 1959 an inch has been exactly 2.54 cm (25.4 mm).
Weight
Kilograms and pounds using the international pound, also shown in pounds and ounces.
Temperature
Fahrenheit, Celsius and Kelvin in any direction, with a warning if a value falls below absolute zero.
Number systems
Binary, octal, decimal and hexadecimal with exact arithmetic and the steps for each conversion.
Exact reference conversions
- 1 inch = 2.54 cm = 25.4 mm
- 1 foot = 12 inches = 30.48 cm
- 1 pound = 0.45359237 kg = 16 ounces
- 1 kg ≈ 2.2046 pounds
- °F = °C × 9/5 + 32 · K = °C + 273.15
- 1 hex digit = 4 bits · 1 byte = 8 bits
Related
Related sections
- Math calculatorsFree math calculators with step-by-step work: fractions, ratios and proportions, GCF, LCM, factors, prime numbers, area and an everyday calculator.
- Loan and debt calculatorsFree loan calculators: mortgage payments, personal and auto loans, full amortization schedules and credit card payoff, with the interest you'll pay in total.