thumb|upright=1.75|An illustration of Dalton's law using the gases of air at sea level.
Dalton's law (also called Dalton's law of partial pressures) states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases. This empirical law was observed by John Dalton in 1801 and published in 1802. Dalton's law is related to the ideal gas laws.
Formula
Mathematically, the pressure of a mixture of non-reactive gases can be defined as the summation:
<math display="block">p_\text{total} = \sum_{i=1}^n p_i = p_1+p_2+p_3+\cdots+p_n</math>
where , , ..., represent the partial pressures of each component.