Kilogram-force Meters to Watt-hours (kgf⋅m to Wh)

1 kilogram-force meter equals 0.002724069444 watt-hours (rounded).

1 kilogram-force meter = 0.002724069444 watt-hours

How to convert kilogram-force meters to watt-hours

To convert kilogram-force meters to watt-hours, multiply the number of kilogram-force meters by 0.002724069444. The factor is rounded to 10 significant digits. To go the other way, multiply watt-hours by 367.0978367 (rounded).

watt-hours = kilogram-force meters × 0.002724069444

Example: 10 kilogram-force meters = 0.02724069444 watt-hours.

The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.

About these units

Kilogram-force Meter (kgf⋅m)

CGS & old metricHistorical unit (no longer in standard use)

Exactly 9.80665 joules, the work of lifting one kilogram by one meter on Earth. Common in older engineering and for torque in Asia.

Kilogram-force meter is the work done when a force of one kilogram-force acts through one meter, a unit of the old gravitational metric system of engineers. Since a kilogram-force is 9.80665 newtons, it equals 9.80665 joules, using the conventional standard gravity adopted in 1901.

Engineers favored it because weights in kilograms could be multiplied directly by heights in meters to give lifting work. The same combination is also used for torque, where NIST lists it against the newton meter with the same factor of 9.80665, and it is sometimes written as kilopond meter.

The kilogram-force was never part of the International System of Units, and the newton replaced it after 1948. Even so, older motor and tool specifications, especially from Asian and European sources, still quote torque in kgf m, and dividing by about ten gives a rough figure in newton meters.

1 kilogram-force meter = 9.80665 joules (exactly).

Sources: Wikipedia: Kilogram-force; NIST SP 811, Appendix B.8 conversion factors; Wikipedia: Centimetre-gram-second system of units

Watt-hour (Wh)

Metric (SI)Current unit

Exactly 3,600 joules, the energy used by a one-watt device in an hour. Battery capacities are quoted in watt-hours.

Pair a power unit with a unit of time and you get the watt-hour: one watt sustained for one hour, which works out to 3,600 joules. The watt itself was adopted at the second International Electrical Congress in 1889, in the same session that adopted the joule, so the two units share a birthday even though the watt-hour is the one people read off batteries.

Battery capacity is where it earns its keep. Multiplying amp-hours by the battery voltage gives an estimate of watt-hours, so a 2,500 mAh lithium-ion cell at 3.7 V holds roughly 9.25 Wh. That is why a 500 mA USB device runs about 3.7 hours on it rather than five: the cell voltage, not the 5 V from the port, sets the energy.

For scale, an alkaline AA battery holds about 9 kJ, which is 2.5 Wh. A 12 W LED lamp left on for an hour uses 12 Wh, and a 40 W appliance running for 25 hours uses 1,000 Wh.

1 watt-hour = 3,600 joules (exactly).

Sources: Wikipedia: Watt-hour; Wikipedia: Joule; Wikipedia: Orders of magnitude (energy)

Related conversions

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