Stoichiometric amount of air:

Theoretically complete combustion can be obtained when stoichiometric amount of air is used.   Stoichiometric amount (also termed theoretical air or air for complete combustion) of air can be calculated by considering the products of combustion obtained on complete combustion. In general any balanced chemical equation (mole input = moles output) can be used to calculate stoichiometric amount of  air.

In combustion equations 1 to 4, we note that 1mole of C requires 1 mole of  or 4.76 moles of air to give 1 mole of  and 3.76 moles of . Similarly 1 mole of H₂ requires  mole of  or 2.38 moles of air to give 1 mole   and 1.88 mole of .