What it calculates
Convert common single-phase electrical values.
Watts / Amps / Volts Calculator
Calculate one common single-phase electrical value from the other two.
Planning and estimating aid only. Verify project requirements, manufacturer instructions, adopted codes, permits, and field conditions before performing regulated work.
Electrical planning
How to Use This Calculator
Use the field units shown below, then compare your result with the worked example. For AC equipment, real power and apparent power can differ.
How the calculation works
For the simple single-phase relationships used here: watts = volts × amps, amps = watts ÷ volts, and volts = watts ÷ amps.
What the result means
Use the mode selector to choose the unknown value and enter the other two values.
Use the right pair of inputs for the selected mode
In Watts mode, enter 10 for current in amps and 120 for voltage. Multiplication gives 1,200 watts under this simple model. In Amps mode, 1,200 divided by 120 gives 10 amps; in Volts mode, 1,200 divided by 10 gives 120 volts.
Contractor tip: For AC equipment, real power and apparent power can differ. Do not use this simple result as a substitute for the equipment nameplate or a complete electrical load calculation.
Verify the final quantity
Read the mode-specific field meaning before entering the two values. The model is simple multiplication or division; it does not include three-phase factors, efficiency or power factor.
Good practice: Compare the calculated quantity with plans, specifications, product packaging and current field conditions before purchasing material.