Mechanical horsepower.
Horsepowers to Zettawatts Converter — hp to ZW
Convert Horsepower (hp) to Zettawatt (ZW) using the exact conversion factor (1 horsepower = 7.456999e-19 zettawatt). See the formula, worked examples, conversion table, history, and common uses.
Horsepowers to Zettawatts converter
Converter
Power Converter
Convert watts, horsepower, refrigeration tons, BTU per hour, and engineering power units.
Context values
Some unit families need one extra value for a physically accurate result.
Zettawatt is 1e+21 watt units.
Result = input x 745.6998716 / 1e+21.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Horsepowers to Zettawatts
Horsepower and Zettawatt both describe power output, and the conversion is a routine part of comparing an engine or motor's spec sheet across countries that use different power units. Horsepower is most often used for us and uk vehicle engine power ratings.
Formula
zettawatts = horsepowers × 7.456999e-19
This factor comes from each unit's defined relationship to the category's base unit: 1 horsepower equals 745.699871582 base units, and 1 zettawatt equals 1e+21 base units, so dividing one by the other gives the direct horsepower-to-zettawatt factor of 7.456999e-19.
Simple example
1 hp × 7.456999e-19 = 7.456999e-19 ZW
1 horsepower = 7.456999e-19 zettawatts.
Real-world example
100 hp × 7.456999e-19 = 7.456999e-17 ZW
100 horsepowers = 7.456999e-17 zettawatts.
Conversion table
| Horsepower (hp) | Zettawatt (ZW) |
|---|---|
| 1 hp | 7.456999e-19 ZW |
| 10 hp | 7.456999e-18 ZW |
| 100 hp | 7.456999e-17 ZW |
| 500 hp | 3.728499e-16 ZW |
| 1,000 hp | 7.456999e-16 ZW |
| 5,000 hp | 3.728499e-15 ZW |
Reverse conversion: Zettawatt to Horsepower
7.456999e-19 ZW × 1.341022e+18 = 1.000000038 hp
7.456999e-19 zettawatts = 1.000000038 horsepowers.
horsepowers = zettawatts × 1.341022e+18
For a page dedicated to this direction, see Zettawatt to Horsepower.
Understanding the Horsepower
Horsepower (hp) measures power. Mechanical horsepower is defined as exactly 745.6998715822702 watts. It is classified as a US/imperial customary unit.
Where it's used: United States and United Kingdom (vehicle and engine specifications)
Mechanical horsepower vs. metric horsepower. Mechanical horsepower (745.7 W) and metric horsepower/PS (735.5 W) differ by about 1.4% — a US car spec sheet in 'hp' and a European one in 'PS' are not directly comparable numbers without conversion.
Uses of the Horsepower today
- US and UK vehicle engine power ratings
- Motor and engine specifications in English-speaking markets
History of the Horsepower
James Watt popularized horsepower in the 1780s as a marketing figure, comparing his steam engines' output to the working capacity of a horse (based on his estimate of a horse turning a mill), so buyers could grasp engine capability in familiar terms. The unit stuck long after its origin as a sales tool, eventually being formally defined at exactly 550 foot-pounds per second.
Historical origin. Horsepower was not the invention of a single named person; it developed through the process described above.
Understanding the Zettawatt (ZW)
Zettawatt is 1e+21 watt units.
Horsepower — sources
- NIST Special Publication 811 — Documents the exact watt-equivalence of mechanical horsepower.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many zettawatts are in 1 horsepower?
1 horsepower equals 7.456999e-19 zettawatts, using the exact defined conversion factor rather than an estimate.
How do I convert horsepower to zettawatt?
Multiply the horsepower value by 7.456999e-19. The converter above does this instantly to whatever precision you set.
How do I convert zettawatt back to horsepower?
Use the reverse factor: 1 zettawatt equals 1.341022e+18 horsepowers. You can also use the swap control in the converter above to flip the direction instantly.
What is a horsepower?
Horsepower (hp) measures power. Mechanical horsepower is defined as exactly 745.6998715822702 watts. It is classified as a US/imperial customary unit.
What is a zettawatt?
Zettawatt (ZW) is a unit of power.
Is the horsepower to zettawatt conversion exact?
Yes. Mechanical horsepower is defined as exactly 745.6998715822702 watts. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between mechanical horsepower vs. metric horsepower?
Mechanical horsepower (745.7 W) and metric horsepower/PS (735.5 W) differ by about 1.4% — a US car spec sheet in 'hp' and a European one in 'PS' are not directly comparable numbers without conversion.
Where is the horsepower still used today?
United States and United Kingdom (vehicle and engine specifications)