Electrical Power Calculator
Calculate electrical power from any two of voltage, current and resistance.
About Electrical Power Calculator
All three power forms follow from Ohm’s law and give the same answer for a consistent set of values. Comparing them is a quick check that the measured voltage, current and resistance agree. The I²R form is the one that matters for losses, because it shows heating rises with the square of current — the reason transmission uses high voltage.
Formula
Electrical Power
P = V I = I² R = V² ÷ R
- P
- Power in watts
- R
- Resistance in ohms
Worked example
With the default values below, Electrical Power Calculator returns Power From Voltage and Current of 2,300.000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Voltageminimum 0 V
- 230 V
- Currentminimum 0 A
- 10 A
- Resistanceminimum 0 ohm
- 23 ohm
Results
- Power From Voltage and Current
- 2,300.000 W
- Power From Current and Resistance
- 2,300.000 W
- Power From Voltage and Resistance
- 2,300.000 W
- Power
- 2.30000 kW
- Energy in 24 Hours
- 55.2000 kWh
Step by step
- 1Values used
- 2Electrical Power
- 3Power From Voltage and Current= 2,300.000 W
- 4Power From Current and Resistance= 2,300.000 W
- 5Power From Voltage and Resistance= 2,300.000 W
- 6Power= 2.30000 kW
- 7Energy in 24 Hours= 55.2000 kWh
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Electrical Power calculated?
P = V I = I² R = V² ÷ R All three power forms follow from Ohm’s law and give the same answer for a consistent set of values. Comparing them is a quick check that the measured voltage, current and resistance agree.
Why does Electrical Power matter?
The I²R form is the one that matters for losses, because it shows heating rises with the square of current — the reason transmission uses high voltage.
What values do I need to enter?
This calculator takes 3 inputs: Voltage, Current, Resistance. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.