Do I have to give the full $800 or $400 to get the tax credit?

You are not required to give the full maximum tax credit of $800 or $400. You may donate any amount up to your limit and receive the credit; up to $800 if you are married and filing jointly, or $400 if you are married and filing separately or a single taxpayer or head of household. For example, if you give $200, you will be eligible for a tax credit of $200. If you give $1,000, you will be eligible for up to a $800 tax credit (married, filing jointly). You may also make convenient monthly donations so that when April 15th arrives, you won’t have to write a big donation check