Units Calculators & Converters
Save to PinterestSix general-purpose unit converters for the quantities people look up most often: length, weight, volume, area, temperature, and speed. Each tool shows all conversions at once — type a value in any unit and every other unit updates live. Conversion factors are sourced from NIST SP 811 and BIPM SI definitions, the same authoritative references used by scientists, engineers, and international trade. Whether you are converting miles to kilometers, pounds to kilograms, or Fahrenheit to Celsius, these tools give you exact values derived from internationally accepted standards.
All Units Tools
Length Converter — m, km, ft, in, yd, mi, cm, mm
Convert between meters, kilometers, feet, inches, yards, miles, centimeters, and millimeters. Live results, NIST-sourced factors.
Weight Converter — kg, lb, oz, g, stone, tonne
Convert between kilograms, pounds, ounces, grams, stone, and metric tonnes. Live results, NIST SP 811 conversion factors.
Volume Converter — L, mL, gallons, fl oz, cups, ft³
Convert between liters, milliliters, US gallons, fluid ounces, cups, and cubic feet. Live results, NIST SP 811 exact factors.
Area Converter — m², ft², acres, hectares, km², sq mi
Convert between square meters, square feet, acres, hectares, square kilometers, and more. Live results from NIST SP 811 exact factors.
Temperature Converter — °F, °C, K
Convert between Fahrenheit, Celsius, and Kelvin. Exact values, NIST SP 811 formulas. Includes absolute zero reference.
Speed Converter — mph, km/h, knots, m/s, ft/s
Convert between mph, km/h, knots, m/s, and ft/s. Live results using NIST SP 811 and BIPM nautical mile definition.