# Energy Measurements and Conversions

File C6-86
Updated October, 2008

pdf format

Deka = ten
Hecto = hundred
Kilo = thousand
Mega = million
Giga = billion
Tera = trillion

1 metric ton = 2204.62 pounds
1 metric ton = 1.1023 short tons
1 kiloliter = 6.2898 barrels (petroleum)
1 kiloliter = 1 cubic meter

## British thermal unit (Btu) measurements and conversions

Approximate definition: A British thermal unit is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

1 British thermal unit (Btu) = 252 International Table calories
1 calorie = .00397 Btus
1 Btu = .252 kilocalories (kcal)
1 kilocalorie (kcal) = 3.968 British thermal units (Btu)
1 Btu = 1,055 joules
1 Btu = 1.055 kilojoules
1 kilojoule = .947817 Btus
1 therm = 100,000 Btus
1 dekatherm = 10 therms
1 dekatherm = 1,000,000 Btus
1 kilowatt hour of electricity = 3,412 Btu
1 horsepower = 2,545 Btu per hour

Convertit: http://www.convertit.com/Go/ConvertIt/Measurement/Converter.ASP
Energy Information Administration: http://www.eia.doe.gov/kids/energyfacts/science/energy_calculator.html
Energy and Work Conversion – Unit Converter: http://www.unitconversion.org/unit_converter/energy.html
BP Conversion Factors: http://www.bp.com/conversionfactors.jsp

## Joule measurements and conversions

Approximate Definition: the energy required to lift a small apple (102g) one meter against Earth’s gravity (Wikipedia).

1 joule = .0009478 Btus
1 Btu = 1,055.05585 joules
1 kilojoule = 1,000 joules
1 kilojoule = .947817 Btus
1 Btu = 1.055 kilojoules
1 kilojoule = .239 kilocalories
1 kilocalorie (kcal) = 4.187 kilojourles (kJ)
1 watt hour = 3,600 joules
1 kilowatt hour = 3.6 megajoules
1 megajoule = 1 million joules
1 terajoule = 1 million megajoules

Online conversions: http://www.onlineconversion.com/energy.htm
Convertit.com: http://www.convertit.com/Go/ConvertIt/Measurement/Converter.ASP
Energy and Work Conversion – Unit Converter: http://www.unitconversion.org/unit_converter/energy.html
BP Conversion Factors: http://www.bp.com/conversionfactors.jsp

## Electricity measurements and conversions

Approximate definition: A human climbing a flight of stairs is doing work at the rate of about 200 watts (Wikipedia).

1 watt = 1 joule per second
1 watt = 3.412 Btu per hour
1 Btu per hour = .293 watts
1 kilowatt (kW) = 1,000 watts
1 kilowatt = 3,412 Btu per hour
1 kilowatt = 1.341 horsepower
1 horsepower = .746 kilowatts
1 megawatt (MW) = 1 million watts
1 gigawatt (GW) = 1 billion watts
1 terawatt (TW) = 1 trillion watts
1 gigawatt = 1 million kilowatts

Watt hours
Approximate definition: One watt-hour is the amount of (usually electrical) energy expended by a one-watt load (e.g., light bulb) drawing power for one hour (Wikipedia).

1 watt second = 1 joule
1 watt minute = 60 joules
1 watt hour (Wh) = 3,600 joules
1 watt hour = 3.6 kilojoules
1 kilowatt hour (kWh) = 3.6 megajoules
1 megajoule = .278 kilowatt hours
1 kilowatt hour = 3,412 Btus
1 kilowatt hour = 860 kilocalories
1 kilowatt hour = 3,600 kilojoules (kJ)
1 kilowatt hour = 1.34 horsepower hours
1 horsepower hour = .746 kilowatt hours
1 kilowatt hour = 1 thousand watt hours
1 megawatt hour (MWh) = 1 million watt hours
1 gigawatt hour (GWh) = 1 billion watt hours
1 terawatt hour (TWh) = 1 trillion watt hours
1 gigawatt hour = 1 million kilowatt hours
1 terawatt hour = 1 billion kilowatt hours
1 terawatt hour = 1 million megawatt hours

Online conversions: http://www.onlineconversion.com/energy.htm
Convertit.com: http://www.convertit.com/Go/ConvertIt/Measurement/Converter.ASP
Energy and Work Conversion – Unit Converter: http://www.unitconversion.org/unit_converter/energy.html
BP Conversion Factors: http://www.bp.com/conversionfactors.jsp

## Power measurements and conversions

1 Btu per second = 1.055 kilowatts
1 Btu per second = 1.415 horsepower
1 Btu per second = 1.434 metric horsepower
1 Btu per second = .252 kilocalories per second
1 kilowatt = .9478 Btu per second
1 kilowatt = 1.341 horsepower
1 kilowatt = 1.36 metric horsepower
1 kilowatt = .2388 kilocalories per second
1 horsepower = .7457 kilowatts
1 horsepower = 1.014 metric horsepower
1 horsepower = .1781 kilocalories per second
1 horsepower = .7068 Btu per second
1 metric horsepower = .9863 horsepower
1 metric horsepower = .7355 kilowatts
1 metric horsepower = .1757 kilocalories per second
1 metric horsepower = .6971 Btu per second

Biomass Energy Data Book, U.S. Department of Energy: http://cta.ornl.gov/bedb/appendix_a.shtml
Power Conversion – Unit Converter: http://www.unitconversion.org/unit_converter/power.html
Online Power Conversion: http://www.convert-me.com/en/convert/power
Energy and Work Conversion – Unit Converter: http://www.unitconversion.org/unit_converter/energy.html

## References

Energy Kids Page, Energy Information Administration, (http://www.eia.doe.gov/kids/energyfacts/science/energy_calculator.html)
Energy Information Administration, (http://www.eia.doe.gov/)
Wikipedia (http://en.wikipedia.org/wiki/Conversion_of_units)
Measurement Converter, Convertit.com, (http://www.convertit.com/Go/ConvertIt/)
Bioenergy Feedstock Information Network, (https://bioenergy.ornl.gov/)
Iowa Energy Center, Iowa State University, (http://www.energy.iastate.edu/)
Biomass Energy Datebook, U.S. Department of Energy, (http://cta.ornl.gov/bedb/appendix_a.shtml)
BP Conversion Factors: http://www.bp.com/conversionfactors.jsp

Don Hofstrand, retired extension value added agriculture specialist, agdm@iastate.edu