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Watts to Amps Converter

Convert watts (W) to amps (A). Because watts measure real power and amps measure electrical current, this calculation requires knowing the voltage of your electrical system.

Watt ↔ Ampere

W
A

Calculation Formula

1,000 W ÷ (120 V × 1 PF) = 8.333 A

Worked Example

Convert 1,200 watts to amps at 120V (Single-Phase, PF=1): 1,200 W ÷ (120 V × 1.0) = 10 Amps

For DC systems, Amps = Watts ÷ Volts. For AC single-phase systems, Amps = Watts ÷ (Volts × Power Factor). For AC three-phase systems, Amps = Watts ÷ (Volts × Power Factor × √3).

Watt to Ampere Table

Note: The conversion tables below assume a Power Factor of 1.0 (ideal). Actual current draw will be higher if the power factor is less than 1.0.
WA (at 120V)A (at 230V)
100 W0.8333 A0.4348 A
500 W4.167 A2.174 A
1,000 W8.333 A4.348 A
1,500 W12.5 A6.522 A
2,000 W16.667 A8.696 A
3,000 W25 A13.043 A
5,000 W41.667 A21.739 A

Understanding the Conversion

Watts represent the actual power consumed, while amps measure the flow of electrical current. To find the current (amps) drawn by a device, you divide the power (watts) by the voltage. For AC circuits, power factor and phase must also be considered.

Frequently Asked Questions

Can watts be converted to amps without voltage?

No. Watts and amps measure different physical quantities. You must know the voltage to convert between them.

How many amps is 1000 watts at 120V?

Assuming a power factor of 1 (resistive load), 1000 watts at 120V is 8.33 amps (1000 / 120 = 8.33).

Does power factor affect watts-to-amps conversion?

Yes, in AC circuits. Real power (watts) accounts for power factor, so current (amps) will be higher for a given wattage if the power factor is less than 1.

Size your backup power system.

Use these converted ratings to determine exactly what size generator or battery bank you need.