Electricity Calculator

Voltage (V)

Current (A)

Resistance (Ω)

Power

Enter any two of V, I, R, P to solve the rest. Values must be positive.

Optional: Energy & Cost

If provided, computes energy (kWh) and cost using solved power.

Electricity Calculator – Quick Cheat Sheet

Enter any two of V, I, R, P to solve the rest.
Ohm’s Law: V = I·R, I = V/R, R = V/I
Power: P = V·I = I²·R = V²/R (watts). 1 kW = 1000 W.
Energy (kWh): Energy = P(W) × hours ÷ 1000
Cost: Cost = Energy × rate (rate is your price per kWh; e.g., 0.15).
Validation: Values must be positive; inconsistent inputs may not be solvable.

Edge cases & notes

Household mains are typically 120 V or 230 V; large appliances may use higher voltages.
Energy & cost require power and time; if rate is omitted, cost is left blank.
Numbers are rounded for display; internal math uses full precision.