How old do you have to be to use spray paint?

i don't know. Probably 9 or older.

Improved Answer: It depends on the municipality. Tempe, AZ will not allow sales or spray paint to minors, while Chicago does not allow the sale of spray paint at all. Also, some companies will not sell spray paint to minors. In New York, stores can not display actual cans of spray paint or markers, only a dummy, nonfunctional can.