Convert Kilojoules to Horsepower-Hours
Convert Kilojoules (kJ) to Horsepower-Hours (hp·h) instantly and accurately.
Conversion Formula
hp·h = kJ × 0.000372506136
About Kilojoules
A kilojoule (kJ) is exactly 1,000 J and is the standard energy unit for food and physical chemistry. EU, Australian, and NZ food labels are mandatory in kJ: recommended adult intake is ~8,400 kJ/day. Bond dissociation energies: C-H bond 413 kJ/mol; C=C double bond 614 kJ/mol; N≡N triple bond 945 kJ/mol. Specific heat of water: 4.184 kJ/(kg·K). A cyclist riding at 150 W for one hour expends 540 kJ. Charpy and Izod impact toughness tests record results in J and kJ. 1 kJ = 1,000 J = 239.0 cal = 0.94782 BTU = 0.27778 Wh.
About Horsepower-Hours
A horsepower-hour (hp·h) is the energy from one mechanical horsepower (745.6999 W) for one hour - exactly 2,684,519.54 J ≈ 2.685 MJ. James Watt coined the horsepower to compare his steam engines with mine horses; billing in hp·h preceded the kilowatt-hour tariff. The metric horsepower (PS = 75 kgf·m/s = 735.499 W) gives a slightly smaller metric-hp·h = 2,647,795 J, used in European and Japanese engine datasheets. Today the hp·h appears in marine engineering logs, mining energy accounting, and vintage industrial equipment. 1 hp·h = 2.6845 MJ = 0.74570 kWh = 641.19 kcal.
Quick Reference Table
| Kilojoules (kJ) | Horsepower-Hours (hp·h) |
|---|---|
| 1 kJ | 0.000372506 hp·h |
| 2 kJ | 0.000745012 hp·h |
| 5 kJ | 0.00186253 hp·h |
| 10 kJ | 0.00372506 hp·h |
| 25 kJ | 0.00931265 hp·h |
| 50 kJ | 0.0186253 hp·h |
| 100 kJ | 0.0372506 hp·h |