Electrical · Problem-solving calculator
Ohm's Law Calculator
Solve for voltage, current, or resistance by entering exactly two values, and calculate the corresponding DC power.
- Free to use
- Runs in your browser
- Level B · Industry formula
- Last reviewed 2026-08-17
Calculator guide
What this calculator helps you solve
Solve for voltage, current, or resistance by entering exactly two values, and calculate the corresponding DC power.
Inputs explained
- Voltage (V) — leave blank if solving — enter the value that applies to your operation or scenario.
- Current (A) — leave blank if solving — enter the value that applies to your operation or scenario.
- Resistance (Ω) — leave blank if solving — enter the value that applies to your operation or scenario.
Formula and methodology
Worked example
With 120 V and 10 A entered, resistance is 12 Ω and DC power is 1,200 W.
How to interpret the result
Use the solved value for basic circuit analysis after confirming the circuit model and measurement basis. Real systems can require additional treatment for AC impedance, phase, temperature, nonlinear loads, or transient conditions.
What to keep in mind
- This calculator uses the ideal resistive DC form of Ohm’s law.
- Enter exactly two values and leave the third field blank.
- Electrical design and safety decisions must follow applicable codes, equipment ratings, and professional requirements.
Review approach
This calculator uses deterministic arithmetic and performs the calculation locally in your browser. Its value comes from combining operational inputs into a decision-oriented result rather than returning a one-line conversion.
Review standard: Level B · Industry formula. How calculator reviews work.
Frequently asked questions
What decision can this calculator support?
Use the solved value for basic circuit analysis after confirming the circuit model and measurement basis. Real systems can require additional treatment for AC impedance, phase, temperature, nonlinear loads, or transient conditions.
How is the result calculated?
V = I × R; I = V ÷ R; R = V ÷ I; P = V × I.
Are the assumptions universal?
No. Operational, regulatory, technical, and industry assumptions vary. Use values that apply to your situation and verify professional or regulatory requirements where relevant.
Does CalculateMeasure store the values I enter?
The calculation runs in your browser and does not require sending the entered calculator values to a server to produce the result.