Ohm’s Law Calculator
Enter the known electrical values and choose what to solve for. This is an educational fixed-resistance estimate, not an equipment-selection or code-compliance result.
- Voltage
- V
- Current
- A
- Resistance
- ohm
- Power
- W
Calculation details
- Calculation basis
- Boundary
Recent results
Formulas
- Voltage = current x resistance
- Current = voltage / resistance
- Resistance = voltage / current
- Power = voltage x current
Use this calculator
Solve voltage, current, resistance, or power from the known values in a simple Ohm law relationship.
Read the result
Review the calculated values with their displayed units and assumptions. The result is a planning aid for the stated inputs, not a final equipment or installation decision.
Check before final work
This is an educational electrical formula estimate. Verify real circuits with measurements, equipment ratings, temperature, waveform, duty cycle, manufacturer data, and qualified review before design or installation decisions.
FAQs
What values do I need for Ohm law?
You need any two related values among voltage, current, and resistance. Power can then be estimated from voltage times current.
Does this work for AC circuits?
It can be used for simple RMS arithmetic when resistance or impedance is known, but it does not model phase angle, reactance, harmonics, or nonlinear loads.
Can this choose a wire, breaker, or component rating?
No. It only performs arithmetic from the entered values and does not select equipment or verify code compliance.