The table below is intended to give one a rough idea of the energy capacity, measured in joules, of various types of entities normally associated with energy. By grouping them all together with joule ratings, it makes comparisons easy and the meaning of energy more understandable. Liquid quantities are given in liters (4.546 liters per gallon) and solid quantities are given in kilograms (2.20 pounds per kilogram). Other quantities are used where common, such as "D-cell" for battery because that is how it is commercially packaged and sold. Some figures in this table are surprising; for instance, they show how little energy value batteries have in comparison to common foods and to fossil fuels. The capacities in this table are drawn from many diverse sources, are meant to be only approximate, and should not be used for rigorous comparisons. Many factors influence the exact energy capacity of a given entity.
| Liquid Fuels in 1-Liter Size | |
| gasoline | 23.0 MJ* |
| kerosene | 31.3 MJ |
| diesel fuel | 31.1 MJ |
| heating oil | 31.9 MJ |
| liquid petroleum gas (compressed propane) | 22.2 MJ |
| liquid natural gas (compressed methane) | 23.1 MJ |
| ethanol (not a fossil fuel) | 19.6 MJ |
| Solid Fuels in 1-Kilogram Size | |
| anthracite coal | 29.0 MJ |
| lignite coal | 16.2 MJ |
| oak wood | 13.4 MJ |
| pine (white) wood | 7.8 MJ |
| Foods in 1-Kilogram Size^ | |
| sugar | 16.5 MJ |
| fat | 37.0 MJ |
| protein | 17.0 MJ |
| carbohydrate | 17.0 MJ |
| alcohol | 29.0 MJ |
| Batteries | |
| lead acid (1 kg) | 0.108 MJ |
| lithium-ion (1 kg) | 0.540 MJ |
| D cell | 0.065 MJ |
| AAA cell | 0.005 MJ |
| 9-volt cell | 0.016 MJ |
| 6-volt lantern battery | 0.238 MJ |
| Miscellaneous | |
| flywheel (1 kg) | 0.500 MJ |
| 100 kg raised 1 km at earth's surface | 0.980 MJ |
| 1000 kg moving at 30 m/s (~ highway speed) | 0.450 MJ |
* MJ = megajoule, M = mega (1,000,000), J = joule
^ recommended daily intake ~ 10 MJ/day for adult male person