Converts between the four ways an AC load is commonly expressed \u2014 real power (kW), apparent power (kVA), reactive power (kVAR) and line current (A) \u2014 for single-phase or three-phase systems. Useful whenever a datasheet, tender document or site measurement gives you one of these figures and you need the others for cable sizing, breaker selection or a load schedule.
Standards followed
AC power-triangle relations (S=β(PΒ²+QΒ²), P=SΒ·PF, Q=SΒ·sinΟ)3-phase / 1-phase current formulas
What it can do
- Converts any one known quantity (kW, kVA, kVAR or Amps) into the other three.
- Handles single-phase and three-phase systems with the correct current formula for each.
- Accounts for lagging, leading or unity load nature when reporting reactive power.
- Flags the two mathematically ill-defined input combinations (kW at PF=0, kVAR at PF=1) instead of returning NaN or dividing by zero.
Example problem
A 415V three-phase load draws 100kW at a lagging power factor of 0.85. Find the apparent power, reactive power and line current.
- Apparent power: S = P / PF = 100 / 0.85 = 117.647 kVA.
- Reactive power: Q = S Γ sin(acos(PF)) = 117.647 Γ sin(acos(0.85)) = 61.968 kVAR.
- Line current (3-phase): I = SΓ1000 / (β3 Γ V) = 117,647 / (1.732 Γ 415) = 163.68 A.
S β 117.6 kVA, Q β 62.0 kVAR, I β 163.7 A.
Want the full step-by-step version?
Two combinations are mathematically undefined and return no result: kW known at PF=0 (a purely reactive load can't determine apparent power from real power alone), and kVAR known at PF=1 (a purely resistive load has zero kVAR).