Think Social Security Will Cover Your Retirement? Here's Why That Assumption Could Backfire.

By Maurie Backman – Apr 8, 2026 at 3:49AM ESTKey PointsIt's not uncommon for seniors to fall back on Social Security for retirement income.Those benefits won't come close to replacing your paychecks in full.You need savings to make up the difference. It's easy to assume that Social Security will pay for all of your needs in retirement. After all, millions of older Americans rely on those benefits today. But you may be overestimating Social Security's role in your retirement income. And it's a mistake that could end up costing you. Image source: Getty Images. The reality of Social Security benefits It's fair to assume that you won't have to replace your pre-retirement paycheck in its entirety once you stop working. At that stage of life, your home might be paid off and your spending needs may be generally lower. But you shouldn't expect to be able to get by on 40% of what you used to earn. And if you retire on only Social Security, that's the reality you may be looking at. One big misconception about Social Security is that it's designed to fully replace workers' paychecks. But you should only expect your monthly benefits to replace about 40% of your former earnings if you make a typical salary. Once you start looking at real numbers, the limitations of Social Security may become clear. A lot of your monthly expenses won't disappear in retirement, even though some may shrink. Housing, groceries, transportation, and healthcare could easily add up to more than what your Social Security benefits cover. And the sooner you realize that, the sooner you can come up with a plan to avoid a shortfall. Use savings to bridge the gap You may only end up needing 70% to 80% of your pre-retirement paycheck to live comfortably as a senior. But if Social Security will only replace 40%, the remainder will need to come from somewhere -- namely, savings you build. To that end, start funding an IRA or 401(k) consistently every month starting now so you have time to grow a nest egg for retirement. And beyond contributing toward savings, invest your money wisely. Choose a variety of stocks with strong financials, or put your money into a few S&P 500 ETFs (exchange-traded funds) if you're not comfortable choosing stocks for your portfolio individually. Let's say you manage to sock away $300 a month for retirement over 25 years. If your investments grow 8% a year, you'll be looking at around $263,000. And from there, withdrawals from your retirement account coupled with Social Security could make it possible to pay your bills without constant worry. Social Security may very well play an important role in your retirement. But it shouldn't be your entire income plan. The more proactive you are about saving to supplement your benefits, the better positioned you should be to maintain your lifestyle and avoid financial stress down the road.Read NextApr 8, 2026 •By James BrumleyThis Is the Average 401(k) Balance for Retirees and It's Not EnoughApr 8, 2026 •By Christy BieberThis Weird Social Security Rule Could Give You Up to 6 Months of Retroactive BenefitsApr 8, 2026 •By Adam LevyRoth IRA Phaseouts for 2025: Are You Still Eligible to Contribute Before the April Deadline?Apr 7, 2026 •By Reuben Gregg BrewerThese Are the 5 Cheapest States to Retire In for 2026Apr 7, 2026 •By Adam LevyWhen to Claim Social Security? The Only 3 Strategies I Recommend.Apr 7, 2026 •By Maurie Backman3 Big RMD Mistakes You Risk Making in RetirementAbout the AuthorMaurie Backman is a contributing Motley Fool retirement and Social Security expert with more than a decade of experience writing about personal finance, investing, and retirement planning. Maurie previously worked in finance analyzing distressed companies. She studied finance at Binghamton University.TMFBookNerd