Power Calculator
Calculate electrical power, voltage, current, and resistance using Ohm's Law and power formulas. Perfect for electrical engineering and circuit analysis.
Power Calculations
Note: Provide at least 2 known values to calculate the unknown value.
Common combinations: V+I, V+R, I+R, P+V, P+I, P+R
Power Formulas
Power Formulas
- P = V × I
- P = V² ÷ R
- P = I² × R
Voltage Formulas
- V = P ÷ I
- V = √(P × R)
- V = I × R
Current Formulas
- I = P ÷ V
- I = V ÷ R
- I = √(P ÷ R)
How the Power calculator works
This free power calculator runs entirely in your browser using standard mathematical formulas. Enter your figures, tap Calculate, and results update instantly — no signup required.
Figures are estimates for general information. Always verify important decisions with a qualified professional where relevant.
- Input your values using the fields above (numeric keypad on mobile).
- Results use precise floating-point arithmetic rounded for display.
- Refresh or change inputs and recalculate anytime.
Worked example
- Choose typical values for a common power scenario.
- Enter those values in the calculator fields above.
- Tap Calculate and compare the on-screen result with the expected formula outcome.
- Adjust one input at a time to see how the result changes.
Frequently Asked Questions
Is the Power calculator free?
Yes. CalculatorQuest tools are free to use, run in your browser, and do not require an account.
How accurate is this power calculator?
It uses standard formulas for this calculation type. Results are estimates — check edge cases and professional advice for critical decisions.
Does it work on mobile?
Yes. Inputs are touch-friendly and open a numeric keypad on phones where appropriate.
Are my numbers stored?
No. Calculations run locally in your browser and are not sent to our servers.