How many kilojoules are in a teaspoon of sugar?

1 rounded teaspoon of table sugar or sucrose (4g) has 68 kilojoules (kJ) of energy.

Sugars have 17 kilojoules (kJ) of energy per gram. This is less than half the energy content of fat (37 kilojoules per gram) and almost half that of alcohol (29 kilojoules per gram).