The Democratic Party always uses a proportional method for awarding delegates. The percentage of delegates each candidate is awarded (or the number of undecided delegates) is representative of the mood of the caucus-goers or the number of primary votes for the candidate. For example imagine a state with ten delegates and three candidates. If 60% of the people supported candidate X, 20% supported candidate Y, and 20% supported candidate Z, candidate X would receive six delegates and candidates Y and Z would each receive two delegates.
The Republican Party, unlike the Democratic Party, allows each state to decide whether to use the winner-take-all method or the proportional method. In the winner-take-all method the candidate whom the majority of caucus participants or voters support receives all the delegates for the state. It is essential to remember that this is a general guide and that the primary system differs significantly from state to state. The best way to find information about your state is to contact your state Board of Elections.