“Only taxes and death are certainties,” goes the old saying. You’re going to keep paying taxes on your income, even after you retire.
Even when retired, you must file annual federal and state income tax returns that catalogue your income streams and compute your taxes.
Retirement income can come from a variety of sources: a pension or annuity, Social Security benefits, a 401(k), investments (stocks, bonds, mutual funds, certificates of deposit, rental property, etc.) and personal savings as well as any continuing part-time employment (depending on job earnings, Social Security benefits are reduced for those who have not reached full retirement age).
Presumably, your total income is less after retirement, and this may move you to a lower tax bracket. However, a lower tax bracket is not guaranteed; it depends on all the variables in your tax return (filing status – individual, joint or married-filing-separately; kinds of income and amounts; deductions; etc.).
Another factor is where you live. Your federal tax will be the same throughout the country, but states vary greatly in how they tax retirement income. Some states have no income tax whatsoever.
On your federal return, Social Security income (SSI) will be taxed. Your adjusted gross income and nontaxable interest are added to one-half of your Social Security benefit to determine your “combined” income. For individuals whose combined income is $25,000-34,000, for example, up to 50 percent of SSI will be taxed. If the combined income is over $34,000, up to 85 percent of SSI will be taxed. Somewhat different scenarios play out for joint or for married-filing-separately returns.