Amps to Watts Calculator
Enter amps and voltage below — result updates instantly.
How do you convert amps to watts?
Multiply amps by volts. A 15 A load on a 120 V circuit uses 15 × 120 = 1800 watts. For AC single-phase, multiply by the power factor too: W = A × V × PF. So 15 A at 120 V with a power factor of 0.9 gives 15 × 120 × 0.9 = 1620 W.
Amps to Watts Formula
In a DC circuit, current equals power divided by voltage. There is no reactive power, so no power factor is needed. Example: a 60 W bulb on 12 V draws 60 ÷ 12 = 5 A.
AC circuits carry reactive power, so the power factor (PF) scales the real power. A PF of 1.0 is perfectly resistive (heaters, incandescent bulbs); motors and electronics typically range from 0.7 – 0.95.
Three-phase power distributes load across three conductors. The √3 factor (≈ 1.732) accounts for the phase angle between conductors. Voltage here is line-to-line (e.g. 400 V in Europe, 208 V or 480 V in the US).
Common Amps to Watts Examples
| Watts | Voltage | Circuit | Result (Amps) |
|---|---|---|---|
| 100 W | 120 V | 0.8333 A | |
| 500 W | 120 V | 4.1667 A | |
| 1,000 W | 120 V | 8.3333 A | |
| 1,500 W | 120 V | 12.5000 A | |
| 2,000 W | 120 V | 16.6667 A | |
| 100 W | 240 V | 0.4167 A | |
| 1,000 W | 240 V | 4.1667 A | |
| 1,500 W | 120 V | 15.6250 A |
Frequently Asked Questions
How do I convert amps to watts?
Divide the power in watts by the voltage in volts. For DC circuits:
A = W ÷ V. For AC single-phase circuits, also divide by
the power factor: A = W ÷ (V × PF). For
AC three-phase: A = W ÷ (V × PF × √3).
Use the calculator at the top of this page to get an instant result.
What is the formula for amps to watts?
There are three formulas depending on circuit type:
- DC:
A = W ÷ V - AC Single-phase:
A = W ÷ (V × PF) - AC Three-phase:
A = W ÷ (V × PF × √3), where √3 ≈ 1.732
PF is the power factor — a value between 0 and 1 that accounts for reactive power in AC circuits. DC circuits always have a power factor of 1.
How many amps is 1500 watts?
It depends on voltage and circuit type:
- 120 V DC: 1500 ÷ 120 = 12.5 A
- 240 V DC: 1500 ÷ 240 = 6.25 A
- 120 V AC single-phase (PF 0.8): 1500 ÷ (120 × 0.8) = 15.625 A
- 240 V AC single-phase (PF 0.8): 1500 ÷ (240 × 0.8) = 7.8125 A
What is the difference between watts and amps?
Current (A) measure electrical
power — the rate at which energy is consumed or produced.
Amps (A) measure electric
current — the rate at which electric charge flows through a conductor.
The two are linked by voltage: W = A × V. A device can draw
few amps at high voltage or many amps at low voltage while consuming the
same wattage. Think of voltage as pressure, amps as flow, and watts as
the total power delivered.