How are FICO Scores calculated for married couples?

Married couples don't have a joint FICO Score, they each have individual scores. The difference is that when you are single you usually only need to worry about your credit habits and profile. However, when you become married your spouse's credit habits and profile have an impact on yours. For example, if you have a credit card in both of your names and it doesn't get paid on time, that can affect both of your FICO Scores - and not in a good way.