Convert Horsepower-Hours to Tons of TNT

Convert Horsepower-Hours (hp·h) to Tons of TNT (t(TNT)) instantly and accurately.

Conversion Formula

t(TNT) = hp·h × 0.0006416155683

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 Tons of TNT

A ton of TNT is an energy unit defined as exactly 10⁹ thermochemical calories = 4.184 GJ. The Trinity test (first nuclear weapon, 1945) yielded ~21 kilotons TNT = 87.9 TJ. The Tsar Bomba yielded ~50 megatons TNT = 209 PJ - the largest human-made explosion in history. Hiroshima's Little Boy yielded ~15 kilotons = 62.8 TJ. The Tunguska 1908 airburst released ~10-15 megatons TNT. Earthquake magnitude 6.0 releases ~63 kilotons TNT equivalent in seismic energy. 1 t(TNT) = 4.184 GJ = 4,184 MJ = 1,162.8 kWh.

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