01
Formula
kVA = √3 × volts × amps ÷ 1,000. kW = kVA × power factor.
Motor amps = HP × 746 ÷ (phase factor × volts × efficiency × power factor). Phase factor is √3 or 1. The power factor calculator is the kW and kVA pair.
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Three phase power calculator for kW, kVA, and motor amps
This three phase power calculator multiplies the square root of 3 by volts and amps. Multiply by the power factor for kilowatts. Without that factor the result is kilovolt-amps, which is the power factor calculator comparison. The motor amperage calculator reverses a horsepower nameplate into full-load amps. These are planning estimates, not a meter reading.
Find
Real power
21.20kW
Apparent power24.94 kVA
Power factor0.85
Formula√3 × V × I × PF ÷ 1,000
Planning estimate from the numbers you enter. Coverage, density, waste and price are assumptions, not a supplier quote or an engineering specification.
How it works
Real power is apparent power times the power factor.
Kilovolt-amps equal the square root of 3 times volts times amps, divided by 1,000. Kilowatts equal that figure times the power factor. Four hundred eighty volts at 30 amps and a power factor of 0.85 is 24.94 kVA and 21.21 kW. The power factor on that mode is a decimal, from just above 0 to 1. The motor amperage calculator uses percent. Full-load amps equal horsepower times 746, divided by the phase factor, volts, efficiency, and power factor. A 10 horsepower motor at 480 volts, 90 percent efficiency, and 85 percent power factor, three phase, draws about 11.75 amps. Single phase drops the square root of 3. Use the nameplate when the motor has one.
02
Example
480 volts, 30 amps, power factor 0.85.
Apparent power is 24.94 kVA. Real power is 21.21 kW. The motor example under the other mode, 10 horsepower at those volts with 90 percent efficiency and 85 percent power factor, is about 11.75 amps.
03
Tips
Do not type a percent into the decimal field.
The power mode wants 0.85, not 85. The motor mode wants 85, because that field is labeled as a percent. Mixing them is off by 100. Three-phase power uses line-to-line volts.
04
Equipment
The service gear and the motor are the purchase.
Dengaro arranges financing for electrical equipment. Amps and kilowatts are not a loan amount.
Important questions
Know what to expect.
What is power factor?+
It is real kilowatts divided by apparent kilovolt-amps. A power factor of 1 means the current is doing all useful work. Lower means some current is magnetizing motors or feeding a similar load. This power factor calculator shows both kW and kVA so you can see the gap.
Why the square root of 3?+
Three phase power sums three lines. The square root of 3, about 1.732, is the factor that turns line-to-line voltage and line current into total power.
Is the motor amperage calculator a breaker size?+
No. It is a full-load amp estimate from horsepower. Breaker and wire rules add their own multipliers. The voltage drop calculator is the wire check. A nameplate FLA beats this estimate.
Can I use single phase?+
Yes, on the motor mode. The power mode is three phase. For single-phase watts, volts times amps times power factor, divided by 1,000, is the kilowatts.
Financing built into the sale