Convert Horsepower-Hours to Megatons of TNT
Convert Horsepower-Hours (hp·h) to Megatons of TNT (Mt(TNT)) instantly and accurately.
Conversion Formula
Mt(TNT) = hp·h × 6.416155683e-10
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 Megatons of TNT
A megaton of TNT (Mt(TNT)) = 10⁶ tons of TNT = exactly 4.184 PJ. The Soviet Tsar Bomba (1961) yielded ~50 Mt - the largest human-made explosion ever, with a fireball 8 km in diameter. Castle Bravo (1954) yielded ~15 Mt, 2.5× its 6 Mt design yield. Modern thermonuclear warheads typically range from 0.1-1.2 Mt. The 2011 Tōhoku earthquake released ~500 Mt in seismic energy. The Krakatoa 1883 eruption released ~200 Mt; Tambora 1815 ~33,000 Mt. 1 Mt(TNT) = 4.184 PJ = 1,162,800 MWh.
Quick Reference Table
| Horsepower-Hours (hp·h) | Megatons of TNT (Mt(TNT)) |
|---|---|
| 1 hp·h | 6.416 × 10-10 Mt(TNT) |
| 2 hp·h | 1.283 × 10-9 Mt(TNT) |
| 5 hp·h | 3.208 × 10-9 Mt(TNT) |
| 10 hp·h | 6.416 × 10-9 Mt(TNT) |
| 25 hp·h | 1.604 × 10-8 Mt(TNT) |
| 50 hp·h | 3.208 × 10-8 Mt(TNT) |
| 100 hp·h | 6.416 × 10-8 Mt(TNT) |