Ohm's Law Calculator
Enter any two known values to calculate the remaining unknowns using Ohm's Law (V = I × R).
Formulas
Ohm's Law: V = I × R
Power: P = V × I = I² × R = V² / R
Where:
V = Voltage (volts, V)
I = Current (amperes, A)
R = Resistance (ohms, Ω)
P = Power (watts, W)
Assumptions & References
- Assumes a linear (ohmic) resistive circuit operating under DC or steady-state AC conditions.
- All values must be non-negative real numbers.
- At least two known values are required; the calculator solves for the remaining two.
- Division by zero is prevented — zero resistance or zero current/voltage where used as a divisor is rejected.
- Ohm's Law: Georg Simon Ohm, Die galvanische Kette, mathematisch bearbeitet (1827).
- Power formula derived from Joule's Law: P = I²R (James Prescott Joule, 1841).