Is a flat or a progressive tax fairer? It depends on your sense of justice — but before you can even answer that question, you need to know how each mechanism works. So students learn that the relative tax burden on individuals depends on which tax base is used. Sales taxes place a higher burden on lower-income people because lower-income taxpayers generally spend a greater percentage of their income than higher-income taxpayers do. A flat income tax is easy to understand: You pay a certain percentage of your income, no matter how much you make. With a progressive income tax, escalating rates apply as income increases. For example, if a married couple had $52,000 of taxable income in 2016, the return they file this year will show a tax liability of $6,872.50 (assuming no tax credits). They will pay 10 percent on their first $18,550 and 15 percent on the rest of their taxable income. Their marginal rate is 15 percent, but their effective, or average, tax rate is 13.2 percent.