How much marijuana can you have on you without being charged?

It varies from state to state.

For example if you are caught in Idaho with any at all, no matter how little you have, you will be arrested. However in California, if you have 28.5 grams of marijuana or less you will not be arrested and will only be required to pay a $100 fine. To check marijuana laws for your state click the link titled "state by state laws", located below.