Electrical calculators
Ohm's law, power, batteries, voltage drop and AC power calculators.
Calculate ohm's law step by step: V = I × R.
Calculate electrical power step by step: P = V × I = I² × R = V² ÷ R (DC or resistive AC using RMS values).
Calculate energy step by step: E (kWh) = P (W) × t (h) ÷ 1,000.
Calculate voltage divider step by step: Vout = Vin × R2 ÷ (R1 + R2).
Calculate current step by step: I = V ÷ R = P ÷ V = √(P ÷ R).
Calculate resistance step by step: R = V ÷ I, or for a conductor R = ρ × L ÷ A (A in m²).
Calculate series resistance step by step: R_total = R1 + R2 + … + Rn.
Calculate parallel resistance step by step: 1 ÷ R_total = 1 ÷ R1 + 1 ÷ R2 + … + 1 ÷ Rn.
Calculate battery runtime step by step: Runtime (h) = Capacity (Ah) × Voltage (V) × DoD × Efficiency ÷ Load (W).
Calculate battery energy step by step: Pack V = cell V × series count; pack Ah = cell Ah × parallel count; Energy (Wh) = pack V × pack Ah.
Calculate voltage drop step by step: Single-phase / DC: Vd = 2 × I × R.
Calculate power factor step by step: PF = P ÷ S = cos φ, and Q = √(S² − P²).
Calculate single phase power step by step: P = V × I × PF; S = V × I.
Calculate three phase power step by step: P = √3 × V_LL × I_L × PF; S = √3 × V_LL × I_L.
Calculate transformer step by step: Vs ÷ Vp = Ns ÷ Np, and for an ideal transformer Ip ÷ Is = Ns ÷ Np.
Calculate led resistor step by step: R = (Vsupply − n × Vf) ÷ I_LED; resistor power P = (Vsupply − n × Vf) × I_LED.