Tons, barrels, cubic feethow do you compare apples and oranges? To make meaningful comparisons of energy commodities, you must convert physical units of measure (such as weight or volume) and the energy content of each fuel to comparable units. One practical way to compare different fuels is to convert them into units of heat content, such as British thermal units (Btu), joules, or calories. The Btu is the measure of thermal energy used most frequently in the United States. The following factors may be used to convert U.S. thermal energy units to metric energy units (joules):
U.S. Units 

Equivalent Metric Units 
1 British thermal unit (Btu) 
= 
1,055.05585262
joules (J) 
1 calorie (cal) 
= 
4.1868 joules (J) 
1 kilowatthour (kWh) 
= 
3.6 megajoules(MJ) 
Not Just for Kids  on the Energy Kid's Page
U.S.
Energy Units Calculator  conversions for common energy units
British
Thermal Units (Btu)  explanation and examples
How
Big is a Barrel?  petroleum
Measuring
Electricity
Measuring
Natural Gas
Scientific
Notation Explained  E + 10?
Factors for Converting Energy Units
General
Conversion Factors  includes physical units per metric ton
Thermal
Conversion Factors  Btu content of common U.S. units (barrel,
cubic foot, short ton, etc.)
Thermal
Conversion Factors  country specific factors
Units
of Measure Equivalents  related to electricity
Overview Discussions
What Is a Btu?
How do I compare heating fuels?  get the answer
How many gallons of gasoline does one barrel of crude oil make?  get the answer


BTU Content of
Common Energy Units
1 barrel (42 gallons)
of crude oil = 5,800,000 Btu
1 gallon of gasoline = 124,000 Btu
1 gallon of heating oil or diesel fuel = 139,000 Btu
1 cubic foot of natural gas = 1,028 Btu
1 gallon of propane = 91,000 Btu
1 short ton of coal = 21,169,000 Btu
1 kilowatthour of electricity = 3,412 Btu


