Amps to Watts Calculator
Multiplies amps by volts (and PF / √3 when selected) to estimate watts.
Limitation: Educational estimate only.
How to Use the Amps to Watts Calculator
Enter the fields below, then review the educational estimate.
Enter current in amps.
Clamp meter tip
Measured amps × volts × PF is a better field estimate than nameplate alone when you can measure safely.
What This Calculator Estimates
Estimates real power from current and voltage using P = V·I·PF·k.
Worked Examples
10 A at 120 V resistive
Inputs
Result
P = 120 × 10 = 1200 W.
10 A at 120 V with PF 0.8
Inputs
Result
P = 120 × 10 × 0.8 = 960 W.
Safety first
De-energize circuits before measuring. When in doubt, stop and consult a licensed electrician.
Frequently Asked Questions
Still have questions about this calculation?
Try the CalculatorFormulas & Assumptions
Transparent educational arithmetic. Not NEC design software or a wiring permit.
Formula
Single-phase / DC
P = V · I · PF
Three-phase
P = V · I · PF · √3
Scientific Background
Shares the same electrical-power engine as the watts-to-amps calculator; only the solved variable changes.
Sources & review
Amps to Watts Calculator documents the references behind its formulas and assumptions. Always treat results as educational estimates, not personalized professional advice.
Last reviewed
July 22, 2026
Reference
physics.nist.gov
https://physics.nist.gov/cuu/Constants/index.htmlReference
nist.gov
https://www.nist.gov/pml/owm/wire-gauge-and-current-carrying-capacityFree Calculator Hub methodology
Free Calculator Hub
/methodology
See our methodology and corrections policy.