Ohm's Law Voltage Calculator

Calculate voltage and resistive power from electrical current in amperes and resistance in ohms for a simple DC load.

Calculate voltage using Ohm’s law

Voltage: 24 VPower: 48 W

How this tool works

Ohm's law relates voltage, current, and resistance for ideal resistive behavior. This focused calculator solves voltage from current and resistance and adds the corresponding power so both electrical relationships can be checked.

Voltage V equals current I multiplied by resistance R. For the same resistive load, power P equals I²R, which is also equivalent to voltage multiplied by current.

How to use it

  1. Enter current in amperes.
  2. Enter non-negative resistance in ohms.
  3. Read calculated voltage and ideal resistive power.

Worked examples

Twelve-ohm load

Input
2 A and 12 Ω
Output
24 V and 48 W

Ohm's law multiplies two amperes by twelve ohms for 24 volts; current squared times resistance gives 48 watts.

Small current

Input
0.5 A and 20 Ω
Output
10 V and 5 W

Half an ampere through twenty ohms requires ten volts, while the resistive power is one quarter times twenty.

Limitations

  • Reactive AC circuits require impedance and phase analysis.
  • Real components have tolerances, temperature effects, and safety limits.