Don't let flashy low rates fool you. To find a loan's true cost, calculate the Effective Interest Rate (APR), which includes compounding frequency and hidden fees. This ensures a fair comparison.

is—it’s effectively a percentage of an amount over a year. If your savings account earns you a 0.05% interest per year (which is a REALLY terrible interest rate, honestly), you earn $5 in interest for ...

Effective tax rate is your average tax rate as a percentage of total income. Marginal tax rate is the tax on your highest dollar earned, not your total income. Historically, top marginal rates have ...