Amps to Watts Calculator
Watts = amps × volts × power factor. A load drawing 5A at 220V uses about 1100W if it's resistive (bulbs, heaters), or roughly 880W for typical home appliances. Enter the current below to find the power.
Convert amps to watts
Enter a value above to see the result.
Quick answers at 220V
| Amps | Watts (resistive) | Watts (0.8 PF) |
|---|---|---|
| 1A | 220W | 176W |
| 3A | 660W | 528W |
| 5A | 1100W | 880W |
| 10A | 2200W | 1760W |
| 15A | 3300W | 2640W |
Watts = amps × 220 × power factor. The 0.8 column is what motor and electronics loads actually consume; the resistive column applies to bulbs and heaters.
Worked example
An IPS that can supply 10A at 220V can run about 1760W of resistive load (bulbs, iron) — or about 1400W of typical mixed home load at a 0.8 power factor. That tells you straight away whether the IPS can handle a 1400W rice cooker, or whether you should keep a high-power appliance off the backup line.
Common mistakes
- Treating battery amp-hours (Ah) as if it were output current (A) — they are completely different measurements.
- Using 12V battery amps as if they were 220V mains amps. A 12V 100Ah battery holds about 1.2kWh, not 100A × 220V = 22kW.
- Forgetting the power factor on motor loads, which makes real watts lower than volts × amps.
Frequently asked questions
Is a 100Ah battery the same as 100 amps?
No. Ah (amp-hours) measures battery capacity — how much energy it stores — while A (amps) measures current at a moment in time. A 12V 100Ah battery stores about 1200Wh (1.2kWh) of energy, which is why it can power a 100W bulb for around 10 hours but still 'deliver' far more than 100A for a split second.
How many watts can my IPS supply?
Check the VA rating on the label and multiply by the power factor (about 0.8 for typical home loads). A 1000VA IPS supplies roughly 800W of real power. Amps on the label are usually the maximum output current at 220V — watts = amps × 220 × power factor.
Why does a 5A fan consume less than 1100W?
Because fans have a power factor below 1. A fan drawing 5A at 220V with a power factor of 0.7 consumes about 770W of real power, even though 5 × 220 = 1100. The remaining 'apparent' power does no useful work but still flows through the wiring.
What's the difference between DC and AC watts?
Watts are watts — the formula (volts × amps × power factor) is the same. The difference is that DC (batteries, solar panels) has no power factor, so it's simply volts × amps. That's why a 12V battery system and a 220V home supply need different amp calculations for the same power.