Your effective rate is the overall average, while the marginal rate is the amount you paid on the last (or next) dollar. If you made $100k, paid $25K in income

Your effective rate is the overall average, while the marginal rate is the amount you paid on the last (or next) dollar. If you made $100k, paid $25K in income taxes, and were in a 33% bracket, your effective rate was 25% and your marginal rate was 33%.