# Watts to Amps Calculator

URL: https://speedycalculator.com/calculators/physics/watts-to-amps/
Last updated: 2026-10-30

> The watts to amps calculator finds the current from power and voltage for DC, single-phase AC and three-phase AC (line-to-line or line-to-neutral voltage), including power factor.

## Inputs

- Current type
- Power (W, kW, MW, hp, mW)
- Voltage (V, kV, mV)
- Power factor

## Results

- Current

## Formula

```
DC: I = P/V · 1-phase: I = P/(V·PF) · 3-phase L-L: I = P/(√3·V·PF) · 3-phase L-N: I = P/(3·V·PF)
```

## Explanation

Knowing the current lets you choose cables, fuses and breakers. A 2 kW heater on 230 V draws about 8.7 A; the same power on a 120 V circuit draws 16.7 A.

### How to use the Watts to Amps Calculator

- **Current type**
- **Power**
- **Voltage**
- **Power factor**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Choose the system, enter the power, voltage and (for AC) power factor.

### Inputs explained

FieldWhat to enterCurrent typeChoose one: DC, AC single-phase, AC three-phase (line-to-line voltage), AC three-phase (line-to-neutral voltage)PowerUnits: W, kW, MW, hp, mWVoltageUnits: V, kV, mVPower factorA number

### Example values

How the main result changes when **Power** changes and everything else stays at the example values above:

Power (W)Current (A)1,0004.34781,5006.52172,0008.69572,50010.86963,00013.04354,00017.3913

## Worked example

Inputs — Current type: AC single-phase; Power: 2,000 W; Voltage: 230 V; Power factor: 1.

Results — **Current = 8.69565 A**.

## Key terms

- **Ampere**: SI unit of electric current.

## FAQ

**How many amps is 1,000 W at 230 V?**
About 4.35 A.

**How many amps is 1,000 W at 120 V?**
About 8.33 A.

**Why does power factor increase current?**
Reactive current flows without delivering real power.

**Which voltage should I use for three-phase?**
Usually the line-to-line voltage (e.g. 400 V).


## Sources

- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)