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Power • NIST Exact

Horsepower → Watts

hp → W

1 hp = 745.69987158 W• NIST Exact

hp → W Reference Table

hp W
0.01 hp 7.456998716 W
0.1 hp 74.56998716 W
0.5 hp 372.8499358 W
1 hp 745.6998716 W
2 hp 1491.399743 W
5 hp 3728.499358 W
10 hp 7456.998716 W
20 hp 14913.99743 W
50 hp 37284.99358 W
100 hp 74569.98716 W
500 hp 372849.9358 W
1000 hp 745699.8716 W

Values based on NIST SP 811 conversion factors

🌍 Real-World Examples

James Watt's original unit definition

1 hp = 745.6998716 W

A typical family sedan engine

150 hp = 111854.9807 W

A small electric drill

0.5 hp = 372.8499358 W

A riding lawn mower engine

10 hp = 7456.998716 W

Why Convert Horsepower to Watts?

Converting between horsepower (hp) and watts (W) is one of the most common power conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert hp to W saves time and prevents errors.

Power conversions between hp and W are essential for automotive, electrical, and HVAC applications. Car specifications in Europe and China list engine power in kilowatts (kW), while the US and Japan prefer horsepower (hp). Home appliance energy labels show wattage for comparing electricity consumption. When sizing generators, air conditioners, or solar panels, accurate power conversion ensures you select the right equipment for your needs.

How to Convert Horsepower to Watts

To convert horsepower to watts, use the following formula:

W = hp × 745.6998716

Example: 1 hp = 745.6998716 W

For example, 5 hp = 3728.499358 W, 10 hp = 7456.998716 W, and 100 hp = 74569.98716 W. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Use Cases

  • James Watt's original unit definition: 1 hp = 745.6998716 W
  • A typical family sedan engine: 150 hp = 111854.9807 W
  • A small electric drill: 0.5 hp = 372.8499358 W
  • A riding lawn mower engine: 10 hp = 7456.998716 W

Common Mistakes to Avoid

  • Horsepower variants: Mechanical horsepower (550 ft·lbf/s) ≈ 745.7 W, while metric horsepower (PS) ≈ 735.5 W. This converter uses mechanical hp.
  • Peak vs continuous power: Motor specifications may list peak or continuous power. A "2000W peak" motor might only sustain 1200W continuously.
  • Electrical vs mechanical: Electrical power (watts) and mechanical output (horsepower) differ by motor efficiency (typically 80-95%).

Pro Tips

  • Memorize the factor: 1 hp = 745.6998716 W. For quick mental math, remember this base conversion.
  • Quick reference: 5 hp = 3728.499358 W · 10 hp = 7456.998716 W · 25 hp = 18642.49679 W · 50 hp = 37284.99358 W · 100 hp = 74569.98716 W
  • Bookmark this page: Save this converter for instant access. It works offline once loaded — no internet needed.

Horsepower to Watts Conversion Table

hpW
0.01 hp7.456998716 W
0.1 hp74.56998716 W
0.5 hp372.8499358 W
1 hp745.6998716 W
2 hp1491.399743 W
5 hp3728.499358 W
10 hp7456.998716 W
20 hp14913.99743 W
50 hp37284.99358 W
100 hp74569.98716 W
500 hp372849.9358 W
1000 hp745699.8716 W

All values in this table are mathematically exact per NIST SP 811.

Frequently Asked Questions

How many watts are in 1 horsepower?

1 hp equals 745.6998716 W. This is an exact conversion factor defined by NIST.

How do I convert horsepower to watts?

Multiply the value in hp by the conversion factor. For example, 10 hp = 7456.998716 W. Use our calculator above for instant results.

Is the horsepower to watts conversion exact?

Yes, this conversion is mathematically exact based on the international definition of these units (NIST SP 811).

Power More Conversions

kW → hp hp → kW W → kW kW → W W → hp