These converters cover the most frequently used SI unit conversions in electrical, energy, and mechanical engineering. All conversions are based on the International System of Units (SI) definitions and standard metric prefixes (kilo = 10³, milli = 10⁻³). The exact conversion factor is shown in each calculator's formula for full transparency.
The system of physical units adopted by the General Conference on Weights and Measures (CGPM). Base units relevant to these converters: watt (W) for power, joule (J) for energy, pascal (Pa) for pressure, and metre (m) for length.
Metric prefixes
kilo (k) = 10³, mega (M) = 10⁶, milli (m) = 10⁻³. Examples: 1 kW = 1000 W; 1 kPa = 1000 Pa; 1 mA = 0.001 A.
Conversion factor
Exact numerical ratio between two units of the same physical quantity. For power: 1 kW = 1000 W. For energy: 1 kWh = 3,600,000 J. For pressure: 1 bar = 100,000 Pa.
Lux and lumens
The lumen (lm) measures total luminous flux emitted by a source. Lux (lx) measures illuminance on a surface: 1 lux = 1 lm/m². Converting lm to lx requires the illuminated surface area as an additional parameter.
Bar, Pa, kPa
The pascal (Pa) is the SI unit of pressure: 1 Pa = 1 N/m². 1 bar = 100,000 Pa = 100 kPa. The bar is not an SI unit but is accepted for practical engineering use.
Core formulas
P [kW] = P [W] / 1000
E [kWh] = E [J] / 3,600,000
E_v [lux] = Φ [lm] / A [m²]
p [kPa] = p [Pa] / 1000 | p [bar] = p [Pa] / 100,000
Applicable standards
BIPM — Bureau International des Poids et Mesures (SI definitions)
IEC 80000-6 — Quantities and units: electromagnetism