Case 1
- Power
- 1500W
- Voltage
- 230V
6.521739A
Open with these valuesWatts to Amps Calculator
6.521739A
Result: 6.521739 ADivide the watts by the volts: a 1500 W heater on 230 V draws 6.52 A. The same heater on 120 V would draw 12.5 A, which is why North American circuits trip sooner. A motor or a switching supply draws more than this — divide again by its power factor.
Worked examples
Case 2
- Power
- 2300W
- Voltage
- 230V
10.000000A
Open with these valuesCase 3
- Power
- 60W
- Voltage
- 12V
5.000000A
Open with these valuesHow it's calculated
I = P ÷ V
- StepRead the power in watts from the rating plate.
- StepEnter the supply voltage — 230 V in Europe, 120 V in North America.
- StepDivide; the result is the current the device draws.
- ResultPick a fuse above that current, not exactly at it.
Reference table
| Power, voltage | Where it turns up | Current |
|---|---|---|
| 60, 12 | A 12 V car lamp | 5.000000 |
| 100, 120 | A US table lamp | 0.833333 |
| 100, 230 | An EU light fitting | 0.434783 |
| 1500, 230 | A fan heater | 6.521739 |
| 2300, 230 | A kettle at 10 A | 10.000000 |
Questions
How do I convert watts to amps?
Divide the watts by the supply voltage. A 2300 W kettle on 230 V draws exactly 10 A.
Which fuse do I need?
One rated above the calculated current, chosen from the standard sizes. A 1500 W heater on 230 V draws 6.52 A and sits comfortably on a 10 A circuit.
Why does the same appliance draw more amps in the US?
Because the voltage is roughly half. At 120 V a 1500 W heater needs 12.5 A instead of 6.52 A, so the wiring has to be thicker for the same power.
Does the power factor matter?
For heaters, kettles and filament lamps, no — they draw current in step with the voltage. Motors, transformers and LED drivers draw more current than this figure; divide the result again by their power factor.
Sources and last check
Information, not professional advice.