Watts to Amps Conversion Chart for 12V, 120V, 208V and 240V
Part of the project planners: Sizing a circuit: watts, amps, wire and breaker and Planning backup power, batteries and solar.
To convert watts to amps, divide the watts by the volts. 1,500 watts at 120 volts is 12.5 amps, and the same load at 240 volts is 6.25 amps. This guide has the chart, the typical current of household appliances, and the formulas for power factor and three-phase. The watts to amps calculator does your own numbers.
Watts to amps chart
Power factor 1 (resistive loads such as heaters and lamps):
| Watts | 12 V DC | 120 V | 208 V | 240 V |
|---|---|---|---|---|
| 100 W | 8.33 A | 0.83 A | 0.48 A | 0.42 A |
| 250 W | 20.83 A | 2.08 A | 1.20 A | 1.04 A |
| 500 W | 41.67 A | 4.17 A | 2.40 A | 2.08 A |
| 750 W | 62.50 A | 6.25 A | 3.61 A | 3.13 A |
| 1,000 W | 83.33 A | 8.33 A | 4.81 A | 4.17 A |
| 1,200 W | 100.00 A | 10.00 A | 5.77 A | 5.00 A |
| 1,500 W | 125.00 A | 12.50 A | 7.21 A | 6.25 A |
| 1,800 W | 150.00 A | 15.00 A | 8.65 A | 7.50 A |
| 2,000 W | 166.67 A | 16.67 A | 9.62 A | 8.33 A |
| 2,400 W | 200.00 A | 20.00 A | 11.54 A | 10.00 A |
| 3,000 W | 250.00 A | 25.00 A | 14.42 A | 12.50 A |
| 3,600 W | 300.00 A | 30.00 A | 17.31 A | 15.00 A |
| 4,800 W | 400.00 A | 40.00 A | 23.08 A | 20.00 A |
| 5,000 W | 416.67 A | 41.67 A | 24.04 A | 20.83 A |
| 7,200 W | 600.00 A | 60.00 A | 34.62 A | 30.00 A |
| 9,600 W | 800.00 A | 80.00 A | 46.15 A | 40.00 A |
Typical appliances
Approximate running watts; check the label on your own appliance:
| Appliance | Watts | Amps at 120 V | Amps at 240 V |
|---|---|---|---|
| Phone charger | 20 W | 0.2 A | 0.1 A |
| LED bulb | 10 W | 0.1 A | 0.0 A |
| Laptop | 65 W | 0.5 A | 0.3 A |
| Television | 150 W | 1.3 A | 0.6 A |
| Refrigerator (running) | 200 W | 1.7 A | 0.8 A |
| Microwave | 1,100 W | 9.2 A | 4.6 A |
| Space heater | 1,500 W | 12.5 A | 6.3 A |
| Hair dryer | 1,800 W | 15.0 A | 7.5 A |
| Dishwasher | 1,800 W | 15.0 A | 7.5 A |
| Clothes dryer (electric) | 5,000 W | 41.7 A | 20.8 A |
| Electric water heater | 4,500 W | 37.5 A | 18.8 A |
| Level 2 EV charger (40 A) | 9,600 W | 80.0 A | 40.0 A |
The formulas
| Circuit | Amps = |
|---|---|
| DC | watts ÷ volts |
| Single-phase AC | watts ÷ (volts × power factor) |
| Three-phase AC | watts ÷ (1.732 × line-to-line volts × power factor) |
- Power factor is 1.0 for heaters and incandescent lamps, and 0.8 to 0.95 for motors and many electronics. A lower power factor means more current for the same watts.
- Voltage: the same power at double the voltage takes half the current, which is why big loads (dryers, ranges, EV chargers) use 240 V.
- Three-phase: use the line-to-line voltage, and the total watts of all three phases.
Why it matters
- Breakers: the amps decide the breaker and the wire. A continuous load needs a breaker rated for 125% of the current. See the breaker size calculator.
- Overloads: add the amps of everything on a circuit. A 15 amp circuit carries 12 amps continuously.
- Generators and inverters: they are rated in watts or VA, and the starting current of motors can be several times the running current.
- Low-voltage systems: 600 watts at 12 volts is 50 amps, so solar, RV and boat wiring needs a thick cable. See the voltage drop calculator.
Electrical work can start fires and cause serious injury or death. Use this for planning and learning, follow your local electrical code, and have a licensed electrician do or inspect household wiring.
Frequently asked questions
How do you convert watts to amps?
Divide the watts by the volts. 1,500 W ÷ 120 V = 12.5 A. For AC with a power factor below 1, divide also by the power factor.
How many amps is 1,500 watts?
12.5 amps at 120 volts, and 6.25 amps at 240 volts.
How many amps is 1,000 watts?
8.33 amps at 120 volts, and 83.3 amps at 12 volts DC.
How many amps is 600 watts at 12 volts?
50 amps. Low-voltage systems draw large currents, so they need thick wire.
How do you convert watts to amps for three-phase?
Divide by 1.732 times the line-to-line voltage times the power factor. 30,000 W at 480 V and a 0.85 power factor is 42.5 A.
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