Convert Horsepower-Hours to Microjoules
Convert Horsepower-Hours (hp·h) to Microjoules (µJ) instantly and accurately.
Conversion Formula
µJ = hp·h × 2684519538000
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.
About Microjoules
A microjoule (µJ) is 10⁻⁶ J - the scale of precision laser ablation, ESD damage events, and individual LIDAR pulses. LASIK eye surgery delivers 0.5-2 µJ per pulse at 193 nm, ablating ~0.25 µm of corneal tissue per pulse. ESD events that destroy IC gates correspond to 1-1,000 µJ; the Human Body Model test discharges ~500 µJ at 2 kV. Q-switched microchip laser pulses for rangefinding are 1-100 µJ. The kinetic energy of a 1 mg grain of sand falling 10 cm is mgh ≈ 0.98 µJ. 1 µJ = 10⁻⁶ J.
Quick Reference Table
| Horsepower-Hours (hp·h) | Microjoules (µJ) |
|---|---|
| 1 hp·h | 2.685 × 1012 µJ |
| 2 hp·h | 5.369 × 1012 µJ |
| 5 hp·h | 1.342 × 1013 µJ |
| 10 hp·h | 2.685 × 1013 µJ |
| 25 hp·h | 6.711 × 1013 µJ |
| 50 hp·h | 1.342 × 1014 µJ |
| 100 hp·h | 2.685 × 1014 µJ |