How do you work out the limiting reagent in a reaction?

The limiting reagent is the chemical substance that isn't in excess in the reaction compared to the other components. The way to calculate which reagent limits the reaction and how it progresses is to calculate the number of moles of each reaction component.
The number of moles is calculated using the following equation: no. moles = mass/formula mass
Say there are 2 moles of reagent A and 2.3 moles of reagent B in a reaction that has a 1:1 stoichiometry of A+B -> C, reagent A would be the limiting reagent.