Electrical Calculator
Power Calculator
Calculate watts and kilowatts from voltage, current, and power factor using a simple single-phase power calculator.
What this calculator does
This power calculator estimates electrical power from voltage, current, and power factor using a simple single-phase power formula.
It is useful for quick checks involving electrical loads, small equipment, general power estimation, and rough consumption analysis.
Inputs
Result
How to read the result
The watt result shows estimated power in watts, while the kilowatt result shows the same value converted to kW for easier comparison with larger loads or electricity cost estimates.
This is best used as a simple reference value, especially when you want a quick estimate rather than a full engineering analysis.
Formula
Power (W) = Voltage (V) × Current (A) × Power Factor
Power (kW) = Power (W) ÷ 1000
Worked example
If voltage is 220V, current is 10A, and power factor is 0.9:
220 × 10 × 0.9 = 1980 W
1980 W ÷ 1000 = 1.98 kW
Common volts, amps, and watts examples
120V and 15A
120 × 15 = 1800W when power factor is 1.
230V and 16A
230 × 16 = 3680W at a power factor of 1.
220V and 10A
220 × 10 = 2200W before applying any power factor adjustment.
240V and 20A
240 × 20 = 4800W when using a simple unity power factor estimate.
When this power calculator is useful
Quick watt estimates
Use this page when you know volts and amps and want a quick watts estimate without doing the formula manually.
Single-phase load checks
This is a good fit for small appliances, lighting, office equipment, and other simple single-phase load calculations.
Cost planning
After estimating watts, use the Electricity Cost Calculator to estimate daily or monthly electricity cost.
Important notes
This is a simple single-phase estimate
This page is intended for a basic single-phase style power estimate. For balanced three-phase systems, use the dedicated 3 Phase Power Calculator.
Power factor affects real power
If power factor is lower than 1, real usable power is lower than the simple voltage × current product.
This is not a full load study
Use this calculator for quick estimation, not for final protection design, wiring decisions, or compliance review.
FAQ
What is power factor?
Power factor represents how efficiently electrical power is being used. A value of 1 means ideal efficiency.
Can I leave power factor as 1?
Yes. For a quick estimate, using 1 is acceptable if you do not have a measured power factor value.
Is this for single-phase power?
Yes. This calculator is intended for a basic single-phase power estimate.
How many watts is 220V at 10A?
At a power factor of 1, 220V and 10A equals 2200W. If power factor is lower, real power will be lower.
How many watts is 120V at 15A?
At a power factor of 1, 120V and 15A equals 1800W.
Why can the actual measured value differ?
Real systems may differ because of varying load behavior, power factor, harmonics, measurement conditions, and equipment characteristics.