Watts to Amps at 12V
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At 12 V DC, amps = watts ÷ 12. A 1,500 W load draws 125 A. Divide any wattage by 12 to get the current at this supply voltage. Use the calculator below for AC circuits and power factor.
How do you convert watts to amps?
To convert watts to amps, divide watts by volts. For example, a 1500 W heater on a 120 V circuit draws 1500 ÷ 120 = 12.5 amps; on a 240 V circuit the same 1500 W draws 1500 ÷ 240 = 6.25 A. For AC circuits, also divide by the power factor: A = W ÷ (V × PF).
Watts to Amps Conversion Table (DC)
Watts to Amps Formula
In practice: why 12 V systems run such high current
At 12 V every 100 W of load costs 8.33 A — roughly ten times what the same appliance would draw from a 120 V outlet. A modest 600 W microwave in a camper therefore becomes a 50 A DC draw, which is why 12 V builds need battery cable rather than household wire. Voltage drop compounds it: over a 10-foot run at 50 A you need 6 AWG simply to stay inside the 3% drop that keeps appliances behaving properly.
Frequently Asked Questions
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 × 1.732).
DC: A = W ÷ V. AC Single-phase: A = W ÷ (V × PF). AC Three-phase: A = W ÷ (V × PF × 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.
It depends on voltage and circuit type. 120V DC: 12.5 A. 240V DC: 6.25 A. 120V AC single-phase (PF 0.8): 15.625 A. 240V AC single-phase (PF 0.8): 7.8125 A.
Watts (W) 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.