Amps To Horsepower Conversion Calculator – Convert Amp to HP

This Amps to Horsepower Calculator helps convert electrical current measurements (amps) into mechanical power output (horsepower).

This handy calculator bridges the gap between electrical and mechanical engineering concepts, making it easier to understand the power capabilities of motors and electrical equipment.

Amps To Horsepower Calculator

Amps to Horsepower Conversion Table (PF = 0.9)

Amps	HP @ 120V (1Φ)	HP @ 220V (1Φ)	HP @ 208V (3Φ)	HP @ 230V (3Φ)	HP @ 460V (3Φ)	HP @ 480V (3Φ)	HP @ 600V (3Φ)
10	1.45 HP	2.66 HP	4.34 HP	4.80 HP	9.60 HP	10.02 HP	12.53 HP
50	7.23 HP	13.28 HP	21.70 HP	24.00 HP	48.00 HP	50.10 HP	62.65 HP
100	14.46 HP	26.55 HP	43.40 HP	48.00 HP	96.00 HP	100.20 HP	125.30 HP
200	28.92 HP	53.11 HP	86.79 HP	96.01 HP	192.01 HP	200.41 HP	250.61 HP
300	43.38 HP	79.66 HP	130.19 HP	144.01 HP	288.01 HP	300.61 HP	375.91 HP
400	57.84 HP	106.22 HP	173.59 HP	192.01 HP	384.02 HP	400.81 HP	501.21 HP
500	72.30 HP	132.77 HP	216.99 HP	240.01 HP	480.02 HP	501.01 HP	626.51 HP
600	86.76 HP	159.33 HP	260.39 HP	288.01 HP	576.03 HP	601.21 HP	751.81 HP
700	101.22 HP	185.88 HP	303.79 HP	336.01 HP	672.03 HP	701.41 HP	877.11 HP
800	115.68 HP	212.44 HP	347.19 HP	384.01 HP	768.03 HP	801.61 HP	1002.41 HP
900	130.14 HP	239.00 HP	390.59 HP	432.02 HP	864.04 HP	901.82 HP	1127.71 HP
1000	144.60 HP	265.55 HP	433.99 HP	480.02 HP	960.04 HP	1002.02 HP	1253.01 HP

🔹 Three-Phase AC:

HP = (√3 × V × A × PF) / 746
Used for: 208V, 230V, 460V, 480V, 600V

🔹 Single-Phase AC:

HP = (V × A × PF) / 746
Used for: 120V, 220V

Power Factor (PF): 0.9 for all

Amps (A)	Voltage (V)	Efficiency	Horsepower (HP)
5 A	120 V	90%	0.725 HP
8 A	120 V	90%	1.16 HP
10 A	120 V	90%	1.45 HP
15 A	120 V	90%	2.18 HP
20 A	120 V	90%	2.9 HP
32 A	120 V	90%	4.64 HP
100 A	120 V	90%	14.5 HP
5 A	220 V	90%	1.325 HP
8 A	220 V	90%	2.12 HP
10 A	220 V	90%	2.65 HP
15 A	220 V	90%	3.975 HP
20 A	220 V	90%	5.3 HP
32 A	220 V	90%	8.48 HP
100 A	220 V	90%	26.5 HP
240 A	220 V	90%	63.6 HP

Amps To Horsepower Conversion Formula

For single-phase AC motors: HP = (V × I × PF × Eff) ÷ 746

For three-phase AC motors: HP = (V × I × PF × Eff × 1.732) ÷ 746

Where:

• HP = Horsepower
• V = Voltage (volts)
• I = Current (amps)
• PF = Power Factor (typically 0.8-0.9 for motors)
• Eff = Motor Efficiency (typically 0.7-0.95)
• 1.732 = Square root of 3 (√3), used for three-phase calculations
• 746 = Conversion factor (746 watts = 1 horsepower)

For DC motors, the formula is simpler: HP = (V × I × Eff) ÷ 746

Convert 20 amps to horsepower for a three-phase motor operating at 460 volts, with 0.85 power factor and 90% efficiency:

HP = (460 × 20 × 0.85 × 0.90 × 1.732) ÷ 746 HP = (12,176.64) ÷ 746 HP = 16.32 horsepower

A three-phase 460V motor drawing 20 amps will produce approximately 16.32 horsepower under these conditions.

How to Convert Amps To Horsepower?

• Determine your power system type:
  • Single-phase AC
  • Three-phase AC
  • DC power
• Gather the necessary information:
  • Voltage (V)
  • Current in amps (I)
  • Power factor (PF) – typically 0.8-0.9 for AC motors
  • Motor efficiency (Eff) – typically 70-95%
• Select the appropriate formula based on your system type
• Substitute your values into the formula
• Calculate the result and express it in horsepower (HP)

Let’s convert 30 amps to horsepower for a single-phase 120V motor with 0.8 power factor and 75% efficiency:

1. Identify system: Single-phase AC
2. Gather info: V=120V, I=30A, PF=0.8, Eff=0.75
3. Select formula: HP = (V × I × PF × Eff) ÷ 746
4. Substitute values: HP = (120 × 30 × 0.8 × 0.75) ÷ 746
5. Calculate: HP = 2,160 ÷ 746 = 2.9 horsepower

This single-phase motor drawing 30 amps at 120V will produce approximately 2.9 horsepower.

What is Amps and Horsepower?

Amps (amperes) and horsepower are fundamentally different measurements that relate to power in electrical and mechanical systems, respectively.

Amps measure electrical current – the flow of electrons through a conductor. Key facts about amps:

• They measure the rate of electron flow
• They’re a fundamental electrical unit
• Higher amp readings indicate greater current flow
• Amps alone don’t tell you power without knowing voltage

Horsepower measures mechanical power output – the rate at which work is done. Key facts about horsepower:

• One horsepower equals 746 watts of electrical power
• It was developed by James Watt to compare steam engine power to horses
• It remains the standard unit for motor power in many countries
• One horsepower represents the power needed to lift 550 pounds one foot in one second

Example 1: Small Workshop Motor

Calculate the horsepower of a single-phase motor running on 240V, drawing 10 amps, with 0.85 power factor and 80% efficiency:

HP = (V × I × PF × Eff) ÷ 746 HP = (240 × 10 × 0.85 × 0.80) ÷ 746 HP = 1,632 ÷ 746 HP = 2.19 horsepower

This workshop motor produces approximately 2.2 HP, suitable for smaller tools like bench grinders or small table saws.

Example 2: Industrial Three-Phase Motor

Calculate the horsepower of a three-phase motor running on 480V, drawing 25 amps per phase, with 0.88 power factor and 92% efficiency:

HP = (V × I × PF × Eff × 1.732) ÷ 746 HP = (480 × 25 × 0.88 × 0.92 × 1.732) ÷ 746 HP = 16,959.64 ÷ 746 HP = 22.73 horsepower

This industrial motor generates approximately 22.7 HP, making it suitable for larger machinery like compressors or production equipment.

Example 3: DC Battery-Powered Motor

Calculate the horsepower of a DC motor running on 24V, drawing 50 amps, with 75% efficiency:

HP = (V × I × Eff) ÷ 746 HP = (24 × 50 × 0.75) ÷ 746 HP = 900 ÷ 746 HP = 1.21 horsepower

This DC motor produces approximately 1.2 HP, typical for smaller electric vehicles, boat trolling motors, or battery-powered equipment.

References

• U.S. Department of Energy – Motor Systems Tip Sheet #11 – Official government publication on motor efficiency and power calculations.
• IEEE Power & Energy Society – Professional engineering organization providing standards and technical information on power systems and motors.