What formula is used?
A = W ÷ V and Ω = V² ÷ W.
Power and Ohm's law
Watts Volts Amps Ohms Calculator
Enter watts and volts to calculate current and equivalent resistance for a resistive DC circuit.
Interactive calculator
Watts Volts Amps Ohms Calculator
Result
10.000 A
Resistance = 12.000 Ω
A = W ÷ V
Live circuit diagram
Watts Volts Amps Ohms Calculator visualized in real time
Values update as you use the calculator.
Input
—
Circuit setting
—
Calculated output
Enter values to see the live result
Quick answers
Watts Volts Amps Ohms Calculator: quick answers
Get concise answers to the most common watts volts amps ohms calculator questions before reviewing the formulas, examples, and detailed guidance below.
What is a practical example?
1200 W at 120 V equals 10 A and 12 Ω.
Does power factor matter?
This simplified combined tool is intended for DC or resistive loads.
Formula
Watts-volts-amps-ohms formulas
Choose the formula that matches the electrical system and known values.
Current
A = W ÷ V
Power divided by voltage.
Resistance
Ω = V² ÷ W
Equivalent resistive load.
Power check
W = V × A
Verify the relationship.
How to use
Calculate in five clear steps
Check every unit and use measured or nameplate values where possible.
- 1. Enter power in watts.
- 2. Enter voltage.
- 3. Calculate current.
- 4. Calculate equivalent resistance.
- 5. Confirm the load is suitably resistive.
Worked examples
Practical calculation examples
Examples make the formula and its assumptions easier to verify.
1,200 W at 120 V
10 A, 12 Ω
2,300 W at 230 V
10 A, 23 Ω
120 W at 24 V
5 A, 4.8 Ω
60 W at 12 V
5 A, 2.4 Ω
4,800 W at 48 V
100 A, 0.48 Ω
1,000 W at 100 V
10 A, 10 Ω
Accuracy
Common mistakes and limitations
The result is only as reliable as the selected formula and input data.
Conversion library
Explore all 44 electrical calculators
Continue from the Watts Volts Amps Ohms Calculator to a dedicated conversion tool for watts, amps, volts, kW, kVA, energy, batteries, or circuit calculations. Each linked page includes its own formula, examples, and guidance.
FAQ
Watts-volts-amps-ohms questions
Direct answers to common calculation questions.
What formula is used?
A = W ÷ V and Ω = V² ÷ W.
What is a practical example?
1200 W at 120 V equals 10 A and 12 Ω.
Does power factor matter?
This simplified combined tool is intended for DC or resistive loads.
Can watts convert alone?
No. Voltage conversion needs current, while apparent-power conversion needs power factor.
Are watts and VA identical?
Only at power factor 1.
Can I use decimal values?
Yes, enter positive values in the displayed units.
Does efficiency matter?
Efficiency is separate and may be required when comparing input and output power.
Can this size equipment?
Use it for planning, then verify ratings, duty, surge, derating, and codes.
Why might measurements differ?
Operating conditions, harmonics, temperature, and meter accuracy can affect measurements.
Can I copy the result?
Yes, use the copy button.
Related calculators
Continue converting electrical values
Use related published tools for the next step in your calculation.
Ohm's Law Calculator
Voltage from current and resistance
Voltage Divider Calculator
Two-resistor output voltage
Amps to kW Calculator
Current to real power
Amps to kVA Calculator
Current to apparent power
Amps to VA Calculator
Current to volt-amperes
All calculators
Browse the complete electrical calculator collection.