SI · imperial
Units
Inch ↔ mm, °C ↔ K, dm³ ↔ L, lbf ↔ N, psi ↔ bar.
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Questions
How many mm is 1 inch?+
Exactly 25.4 mm. That is the international inch since 1959 (ISO 1). 1 ft = 12 in = 304.8 mm.
Is 1 dm³ the same as 1 L?+
Yes. The litre is defined as 1 dm³, so 0.001 m³. 1 mL = 1 cm³.
Celsius to kelvin?+
T/K = t/°C + 273.15. 0 °C = 273.15 K; 20 °C = 293.15 K. Fahrenheit: T/K = (t/°F + 459.67) × 5/9.
pk or hp?+
pk is metric horsepower (735.49875 W). hp is mechanical horsepower (745.69987 W). For IEC motor steps use kW, not pk.
US gallon or UK gallon?+
US liquid gallon = 231 in³ = 3.785411784 L. Imperial (UK) gallon = 4.54609 L. They are not interchangeable.