Watts Amps Volts Calculator

Direction

Power, W

Voltage, V

Supply

Advanced options

Power factor

Result

Current, A10
Power, W2,200
Power, kW—
Apparent power, VA2,200
Breaker rating10 А
Supplyоднофазная

The question every appliance connection starts with

Converts power to current and back for single-phase and three-phase supplies, and suggests a breaker rating.

Appliances are labelled in watts while breakers and cables are chosen in amps. The conversion is a division by voltage — except in a three-phase supply, where a factor of root three appears and is regularly forgotten.

Power factor matters for anything containing a motor or a ballast. A kettle sits at one, but a pump or a welder can drop to 0.7, and the real current is then noticeably higher than a plain division suggests.

What this calculator shows

Current in amps or power in watts, whichever you asked for
Apparent power in volt-amps when the power factor is below one
A suggested breaker rating for that current

What to keep in mind

Three-phase uses line voltage and the root-three formula, which is how domestic and design calculations are done.
The breaker hint follows the standard range; the final choice always goes together with cable size.

FAQs

How many amps in a kilowatt?

About 4.5 A at 220 volts. The same kilowatt on a 380 volt three-phase supply draws only 1.5 A, because the load is spread across three phases.

What is the power factor for?

It says what share of the drawn current does useful work. Heaters and filament lamps sit at one; motors run 0.7 to 0.85 and pull more current for the same output.

How do I pick a breaker from a wattage?

Work out the current, take the next standard rating — 6, 10, 16, 20, 25, 32 A — then check the cable can carry that breaker. The breaker protects the cable, not the appliance.

Why is the three-phase formula different?

Because the three phases are 120 degrees apart and add as vectors, not arithmetically. That is where the root-three factor of about 1.73 comes from.

Worked example

A kettle on a socket

Input: 2,200 W at 220 V, single phase

Output: 10 A, a 16 A breaker suits

Note: A breaker rated at exactly 10 amps would trip on every surge. You take the next size up, then size the cable to the breaker rather than to the appliance.

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Watts Amps Volts Calculator

Result

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