Watts to Amps Calculator

How to use

1. 1Choose the direction at the top: Watts to amps to find current from a wattage, or Amps to watts to find power from a current draw.
2. 2Choose the circuit type: DC for batteries and low-voltage rails, AC single-phase for household outlets, or AC three-phase for industrial or commercial loads.
3. 3Enter the power or current value, and pick the unit chip (W, kW, mW, or hp for power; A or mA for current). Enter the voltage with V or kV, or click a Common voltages chip such as 12 V, 120 V, 230 V, 240 V, 208 V, 400 V, or 480 V.
4. 4For AC modes, set the Power factor between 0 and 1. Use 1.0 for resistive loads such as heaters, around 0.9 for LED drivers and modern electronics, and 0.7 to 0.85 for motors. Or click a PF preset chip.
5. 5Read the Result panel for the converted current or power, the apparent power in VA or kVA on AC circuits, and the exact formula used. Click Copy summary to grab the full breakdown.
6. 6Compare the formulas in the Quick reference table at the bottom for DC, single-phase, and three-phase circuits.

About this tool

Watts to Amps Calculator is a complete browser-based converter for the three electrical contexts that account for almost every real-world question about power and current: direct current (DC) circuits, AC single-phase circuits, and AC three-phase circuits. In DC mode the math is the textbook P = V * I, which solves the everyday questions for batteries, USB rails, automotive 12 V or 24 V systems, RV and marine 12 V or 24 V loads, and 48 V solar arrays. In AC single-phase mode the tool applies P = V * I * PF, which is the correct formula for residential 120 V outlets in the US, 230 V outlets in Europe, and 240 V dryer or oven circuits, and for any motor, electronics, or LED load where the power factor (PF) is below 1. In AC three-phase mode the tool applies P = sqrt(3) * V_LL * I * PF using line-to-line voltage, which matches industrial 208 V, 400 V, and 480 V distribution, commercial HVAC, EV fast chargers, and any three-phase motor nameplate. You can switch direction at any time: type a wattage to get the current in amps, or type a current in amps to get the load in watts. Inputs accept watts, kilowatts, milliwatts, or mechanical horsepower for power; volts or kilovolts for voltage; and amps or milliamps for current, so you do not have to convert by hand. A power factor field appears for the AC modes with presets for resistive loads at 1.0, switching power supplies at 0.95, LED drivers at 0.9, modern motors at 0.85, and older motors at 0.7. Voltage chips drop common rails into the field in one click: 5 V USB, 12 V auto, 24 V RV, 48 V solar, 120 V US outlet, 230 V EU outlet, 240 V US dryer, 208 V three-phase, 400 V three-phase EU, and 480 V three-phase US. The result panel shows the answer in the most readable unit (mA, A, W, kW, hp), the apparent power in VA or kVA for AC circuits, the formula used, and a Copy summary button that exports every value as a plain-text block for documentation. Useful for sizing breakers and wire gauges to a load, picking the right inverter or generator for a piece of equipment, working out the current draw of a heater or motor on a known circuit, computing the kilowatt rating of an EV charger from its current, and any back-of-the-envelope sanity check in a workshop, lab, or jobsite. Every calculation runs in your browser; the values you enter never leave your device, and there is no signup or upload at any point.

Free to use. Works in your browser. No signup, no login.