Watts to Amps Calculator
Convert between watts and amps at any voltage — switch direction below, or use the 120V and 12V presets for a standard US outlet or a power station's DC port.
The Formula
Watts, volts, and amps are related by a single fixed equation — Ohm's law applied to power. Once you know any two, you can always find the third.
When You'd Need This Conversion
- Sizing a circuit breaker, extension cord, or fuse for a known wattage load.
- Checking whether a 12V DC accessory (car port, solar input) will overload its rated amperage.
- Comparing a device's amp draw against what an outlet or power strip is rated for.
- Converting a spec sheet that only lists amps into watts you can compare against a power station's output rating.
Sizing a power station instead of an outlet or circuit? Our runtime calculator and ports explained guide are the more direct tools for that.
Frequently Asked Questions
What voltage should I use for a standard US wall outlet?
120V is the standard for residential US wall outlets. Large appliances on a dedicated circuit (some dryers, ranges) may use 240V — check your specific outlet or breaker rating if you're unsure.
Why does my device's actual amp draw seem higher than this calculation?
This calculator uses the basic P = V × I formula, which assumes 100% power factor. Some devices, especially those with motors, run at a lower power factor, meaning real-world amp draw can run somewhat higher than the simple calculation suggests. Treat the result as a close estimate, not an exact reading.
What voltage do power station DC ports use?
Most power station car-style ports output 12V DC, matching a standard vehicle accessory outlet. Solar input voltage varies by model — check your specific unit's spec sheet rather than assuming a standard voltage.