Rangdom

Solve a DC circuit from any two of voltage, current, resistance, and power

Enter exactly two of the four quantities — Voltage in volts (V), Current in amps (A), Resistance in ohms (Ω), and Power in watts (W) — and the remaining two are derived from Ohm’s Law and the power equations: V = I·R, P = V·I, P = I²·R, P = V²/R, V = √(P·R), and I = √(P/R). All four values update live as you type, shown to two decimal places as bare numbers in base units.

An inline error appears instead of a result when a field is non-numeric or negative, when fewer or more than two fields are filled, or when the chosen pair would divide by zero (for example a resistance of 0 with power given, or a current of 0 when solving for resistance) — so it never renders NaN or Infinity. DC only with base units (V, A, Ω, W) — AC analysis, reactance, impedance, phase, complex numbers, unit-prefix scaling (mA, kΩ), and series or parallel network solving are out of scope.