# Electrical Formulas: How to Calculate Amps, Horsepower, Kilowatts, and kVA for DC and AC Motors

## Use formulas in this chart to calculate amperes (amps), horsepower (HP), kilowatts (kW), and kilovolt-amps (kVA) for Direct Current (DC), Single Phase AC, and Three Phase AC Motors.

### Equations for DC Motors

To Find:
Amperes when
HP is known
_HP x 746_
E x %EEF
Amperes when
kW is known
kW x 1000
E
Amperes when
kVA is known

Horsepower (HP) E x I x %EEF
746
Kilowatts (kW) E x I
1000
Kilovolt-Amperes (kVA)
E = Voltage | EFF = Percent Efficiency | PF = Power Factor of Motor | I = Amps

### Equations for Single Phase AC Motors

To Find:
Amperes when
HP is known
___HP x 746___
E x %EEF x PF
Amperes when
kW is known
kW x 1000
E x PF
Amperes when
kVA is known
sVA x 1000
E
Horsepower (HP) E x I x %EEF x PF
746
Kilowatts (kW) E x I x PF
1000
Kilovolt-Amperes (kVA) E x I
1000
E = Voltage | EFF = Percent Efficiency | PF = Power Factor of Motor | I = Amps

### Equations for 3 Phase AC Motors

To Find:
Amperes when HP is known _____HP x 746_____
E x %EEF x PF x √3
Amperes when kW is known kW x 1000
E x PF x √3
Amperes when kVA is known kVA x 1000
E x √3
Horsepower (HP) E x I x %EEF x PF x √3
746
Kilowatts (kW) E x I x PF x √3
1000
Kilovolt-Amperes (kVA) E x I x √3
1000
E = Voltage | EFF = Percent Efficiency | PF = Power Factor of Motor | I = Amps

Warning: When using this information to perform electrical work, call a licensed electrician and consult the NEC® for safety. All licensed electricians have passed examinations covering the National Electric Code®, know state and local building codes, and may carry insurance to cover damages.