Energy Terms & Formulas

We occasionally get questions from customers about terms and formulas used in the energy business. Here are a few electrical conversion formulas for determining amperes, horsepower, kilowatts, and kilovolt amperes when other factors are known.

Electrical Conversion Formulas for three-phase AC power:

• E represents volts
• I represents amps
• Eff represents motor efficiency
• PF represents power factor
• If PF is not known, assume 0.85
• If Eff is not known, assume 0.90

To find Amps when Horsepower is known:
Amps = (hp × 746) ÷ (1.73 × E × Eff × PF)

To find Amps when Kilowatts are known:
Amps = (kW × 1000) ÷ (1.73 × E × PF)

To find Amps when Kilovolt Amperes are known:
Amps = (kVA × 1000) ÷ (1.73 × E)

To find Kilowatts when Amps, Volts and Power Factor are known:
kW = (I × E × 1.73 × PF) ÷ 1000

To find Kilovolt Amperes when Amps and Volts are known:
kVA = (I × E × 1.73) ÷ 1000

To find Kilowatts when Kilovolt Amperes and Power Factor are known:
kW = (kVA × PF)

To find Kilowatts when Horsepower and Eff are known:
kW = hp × 0.746 ÷ Eff

Electrical Conversion Formulas for single-phase AC power:

• E represents volts
• I represents amps
• PF represents power factor
• If PF is not known, assume 0.85
• If Eff is not known, assume 0.90

To find Amps when Horsepower is known:
Amps = (hp × 746) ÷ (E × Eff × PF)

To find Amps when Kilowatts are known:
Amps = (kW × 1000) ÷ (E × PF)

To find Amps when Kilovolt Amperes are known:
Amps = (kVA × 1000) ÷ (E)

To find Kilowatts when Amps, Volts and Power Factor are known:
kW = (I × E × PF) ÷ 1000

To find Kilovolt Amperes when Amps and Volts are known:
kVA = (I × E) ÷ 1000

To find Kilowatts when Kilovolt Amperes and Power Factor are known:
kW = (kVA × PF)

To find Kilowatts when Horsepower and Eff are known:
kW = hp × 0.746 ÷ Eff