Ohm's law & power calculator
Enter any supported pair of independent electrical values and see voltage, current, resistance and power in one consistent DC resistive model.
V=12 V; I=2 A; R=6 Ω; P=24 W
Steady DC/resistive mathematics only. No AC phase, reactance, transient behavior, tolerance, heat, rating or safety sizing.
Included
- Six valid two-value combinations across voltage, current, resistance and power
- SI-prefix conversion to normalized V, A, Ω and W
- All four electrical quantities plus the substituted equations
Not included
- AC phase, reactance, transients and non-ohmic behavior
- Component tolerance, power rating, thermal design and safety sizing
- Wiring, protection or installation advice
What this means
Ohm's law relates voltage, current and resistance through V = I × R. Resistive electric power is P = V × I. Combining and rearranging those equations produces each supported two-value solve mode.
Every input is converted to V, A, Ω or W before the equations run. Results are then shown with a readable SI prefix without changing the base-unit calculation.
The model requires two positive independent values. Zero resistance would imply an unbounded ideal current in some modes, so zero and non-finite states are rejected rather than displayed as a physical result.
Formula & worked example
V = I × R I = V ÷ R R = V ÷ I P = V × I = I²R = V² ÷ R
12 V and 2 A in a steady resistive DC circuit
- Resistance
- 12 V ÷ 2 A = 6 Ω
- Power
- 12 V × 2 A = 24 W
The same solved values satisfy both Ohm's law and the resistive power identity.
How this calculation works
The calculation follows the formulas, definitions and assumptions explained on this page. The references below support the method and any stated boundaries.
Official sources
- OpenStax Physics — electrical key equations — Ohm's law V = IR, series and parallel resistance, and electric power P = IV
- NIST — SI units for electric current — The volt, ampere and ohm relationships used for base-unit normalization
- NIST — metric SI prefixes — Decimal prefix factors used for milli, kilo and mega display units