Disposable income is the amount of personal income an individual has after taxes. Economists often use disposable income to figure out consumer spending and saving rates. For example, someone with a $100,000 income in the 24% tax bracket has disposable income of $100,000 - $24,000 = $76,000.
Disposable income is often confused with discretionary income. Discretionary income is calculated based on disposable income. Discretionary income is net of living expenses. Using the above example, $76,000 minus $25,000 in living expenses leaves $51,000 in discretionary income. The government uses a slightly different formula to calculate disposable income for wage garnishment purposes. It subtracts health insurance premiums and involuntary retirement plan contributions from gross income.