How to Calculate Amps to Watts
What is Amps to Watts?
An amps to watts converter calculates electrical power from current and voltage. Used to determine the wattage of appliances and the capacity needed from a power source.
Formula
W (DC) = A × V; W (AC) = A × V × PF
- A
- Current (A) — Electrical current in amperes
- V
- Voltage (V) — Electrical potential in volts
- W
- Power (W) — Electrical power in watts
- PF
- Power factor ((dimensionless)) — For AC loads; typically 0.8–1.0
Step-by-Step Guide
- 1Watts = Amps × Volts (DC)
- 2Watts = Amps × Volts × Power Factor (AC)
- 3Power factor for motors is typically 0.8–0.95
- 4Standard voltages: 120V US, 230V EU, 240V UK
Worked Examples
Input
13 amps at 240V
Result
3,120 watts (standard UK plug max)
Input
20 amps at 120V
Result
2,400 watts (US circuit)
Input
32 amps at 240V
Result
7,680 watts (EV charger)
Frequently Asked Questions
How do I calculate watts from amps?
Multiply amps by volts. In AC, also multiply by power factor. Example: 10 A × 240 V = 2,400 W.
Why does my kettle pull more amps than my TV?
The kettle uses more power (watts). At the same voltage, higher wattage means higher amps. Ohm's law: W = V × A.
What's a safe amperage for a standard outlet?
In the US, 15–20 A circuit breakers are standard, supporting 1,800–2,400 W at 120 V. In UK, 13 A plugs support 3,120 W at 240 V.
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