Enter what you have, what you need, and what you expect from Social Security. We run the year-by-year math, apply state tax on Social Security where it applies, and tell you how long the runway actually lasts.
Let's lay it out on the table, man. Most retirement calculators out there are built to make you feel okay, not to tell you the truth. They assume you'll die at 85. They quietly ignore state tax on Social Security. They use a fantasy 7 percent return with no market downturn. And when you hit the button, they spit out a number with no explanation of how they got there.
That's the Longevity Turd. The one who looks at you at 50, sees $350,000 in savings, and says "you're fine" because he quietly rounded your lifespan down to what the actuary tables said in 1980. You are not going to die at 85. Roughly one in four 65-year-olds today will reach 90. One in ten will reach 95. If your runway ends at 85 and you don't, the last ten years of your life are going to be very different from what the calculator promised.
FigureNerd doesn't do rosy. FigureNerd runs the math out to 100, factors in the state tax on Social Security that ten states still impose, inflation-adjusts your spending to retirement age, and tells you whether the runway actually reaches the end of the plane or stops halfway down.
Run the numbers. Then decide what to change.
In 1994, a financial planner named William Bengen looked at 70 years of US stock and bond returns and asked a simple question. What withdrawal rate could a retiree take from a 60/40 portfolio, adjusted for inflation every year, and still have money left after 30 years, even if the retirement started at the worst possible moment in history?
His answer was 4 percent. Take 4 percent of the starting balance in year one. Adjust that dollar amount for inflation every year after. Do that for 30 years and, in almost every historical window, you ended up with money left over.
This became the "4 percent rule" and it's everywhere. Here's why it's wrong for most people.
One, it assumes a 30-year retirement. If you retire at 60 and live to 95, you need 35 years, not 30. The rule breaks down if the runway is longer than Bengen tested.
Two, it assumes steady inflation-adjusted withdrawals. Real retirees don't spend a flat, inflation-adjusted number. They spend more in the early "go-go" years, less in the middle, more again at the end for healthcare. Research by David Blanchett at Morningstar models this "retirement spending smile" and shows real spending falls about 1 to 2 percent per year in real terms through middle retirement.
Three, it ignores taxes. 4 percent of your nest egg is the withdrawal. The amount you keep depends on whether that nest egg is pre-tax (traditional IRA, 401(k)), post-tax (Roth), or taxable (brokerage). A $1,000,000 traditional 401(k) with a 4 percent withdrawal gives you $40,000 gross, maybe $32,000 to $34,000 after federal and state income tax. The $1,000,000 nest egg isn't $40,000 of spending power.
Four, recent research suggests it's too aggressive for today's valuations. Morningstar's 2023 and 2024 safe-withdrawal research lands closer to 3.3 to 4.0 percent when starting valuations are elevated, which they currently are. Wade Pfau's research uses 3.0 to 3.5 percent as a more defensible floor.
The runway calculator above lets you dial the safe-withdrawal rate lower (try 3.5 percent). You'll see the nest egg needed jumps about 14 percent. That's the honest cost of using a more conservative rate.
Here is the gap almost no retirement calculator handles. As of 2026, 10 states still tax at least some of your Social Security benefits at the state level. Most retirees don't know this until they file their first tax return in retirement and see the hit.
Rules vary a lot by state. Most offer income-based exemptions that shield lower-income retirees entirely. Higher-income retirees in these states typically see somewhere between 3 percent and 12 percent of their benefit taxed away. This calculator applies an approximate 5 to 10 percent haircut as a planning estimate. Your actual haircut depends on your total income, filing status, and exemption thresholds.
| State | Approx. SS tax haircut | Note |
|---|---|---|
| Colorado | ~0 to 5% | Exemption for most retirees 65+; partial for 55 to 64 |
| Connecticut | ~0 to 7% | Income-based, phases in at higher incomes |
| Kansas | ~0 to 5% | Exempt below AGI threshold; above it the benefit is fully taxable |
| Minnesota | ~0 to 10% | Income-based subtraction; partial exemption expanded in 2023 |
| Montana | ~0 to 7% | Taxes SS in line with federal treatment |
| New Mexico | ~0 to 5% | Exempt below income threshold (2022 reform) |
| Rhode Island | ~0 to 6% | Modified AGI-based exemption at full retirement age |
| Utah | ~0 to 5% | Retirement credit can offset much or all of the tax |
| Vermont | ~0 to 8% | Income-based exemption |
| West Virginia | ~0 to 5% | Phasing out through 2026, near full exemption now |
If you're in one of these 10, and you have flexibility, moving to a state that doesn't tax Social Security is worth a real conversation with your CPA. The other 40 states (plus DC) exempt Social Security from state tax entirely. For a retiree with $30,000 a year in Social Security, the difference between a full-tax state and a no-tax state can be $1,500 to $3,000 a year. Over a 25-year retirement, that's $37,500 to $75,000 of buying power.
Most people who run honest runway numbers for the first time find a gap. The runway ends at 88, not 95. Or the monthly gap is negative by a few hundred dollars. That doesn't mean the plan is broken. It means you have levers. Here are the five that actually move the needle.
The most direct lever. Every extra $500 a month saved for 15 years at 6 percent return adds about $145,000 to your nest egg. Look for hidden capacity: the employer 401(k) match you're not capturing, the Roth IRA contribution you're skipping ($7,000 in 2026 if you're under 50, $8,000 if you're 50-plus), the catch-up contribution in a 401(k) ($7,500 extra for 50-plus).
Delaying retirement from 65 to 67 does three things at once. You contribute two more years. Your investments grow two more years. Your retirement is two years shorter. Combined impact on a typical retirement plan is a 15 to 20 percent improvement in runway. Delaying to 70 is roughly a 35 to 45 percent improvement, because Social Security also gets permanently bigger.
Unloved but mathematically powerful. Dropping your target spending from $65,000 to $60,000 per year lowers the nest egg you need by about 8 percent. Most of the "spend less" opportunity lives in housing (downsize, pay off mortgage, move) and healthcare (Medicare Advantage vs Medigap trade-offs). A fee-only financial planner earns their fee quickly by finding these.
The single highest-return move the system offers. Every year you delay Social Security between your full retirement age (67 for most people born after 1960) and 70 adds roughly 8 percent to your benefit, permanently, inflation-adjusted. Claiming at 70 instead of 62 is a permanent 77 percent larger check. For most healthy retirees, this is the closest thing to a free lunch in retirement planning.
A $65,000 retirement in Phoenix is very different from a $65,000 retirement in Boston. If you live in a high-cost state that also taxes Social Security, moving to a low-cost state that doesn't can stretch the same nest egg 15 to 30 percent farther. Not everyone wants to move. For those who are open to it, this is often the biggest single lever on the list.
The calculator up top tells you the gap in dollars. The five levers above tell you how to close it. Pick the one that fits your life, not someone else's retirement article. Pulling any one of them, consistently, is what keeps the runway long enough.
The 4 percent rule is a "static" withdrawal strategy. You lock in a dollar amount in year one and inflation-adjust it forever, no matter what the market does. That's simple but inefficient. If the market crashes in year two, you keep withdrawing the same real amount and risk running out. If the market rips for a decade, you keep withdrawing the same boring amount and leave money unspent.
Dynamic strategies adjust withdrawals based on portfolio performance. The most famous is Guyton-Klinger, developed in 2006. Guyton-Klinger defines "guardrails" around your target withdrawal rate. If returns are great and the portfolio grows, you can raise your withdrawal. If returns are bad and the portfolio shrinks, you cut your withdrawal modestly (usually 10 percent) until things recover.
Another is floor-and-ceiling, which sets a minimum and maximum withdrawal in real terms. You can't spend below the floor (you need to live) and you can't spend above the ceiling (you're depleting too fast).
In retirement-research stress tests, dynamic strategies typically support a 4.5 to 5.5 percent starting withdrawal rate with the same portfolio-survival odds as a static 4 percent. That's meaningful. It's the difference between a $1,000,000 nest egg supporting $40,000 a year and $45,000 to $55,000 a year.
The tradeoff is discipline. You have to actually cut spending in down markets. Many retirees don't, and the math stops working.
The calculator above uses a static withdrawal model to keep the output readable. If you want to run dynamic stress tests, free tools like the ones linked above can do it. The runway number FigureNerd gives you is a conservative baseline, not an upper ceiling.
A retirement runway calculator projects how long your retirement savings will last, year by year, from the age you retire until your money runs out or you reach age 100. It grows your current savings with compound interest and contributions, inflation-adjusts your spending target, adds Social Security and any pension income, subtracts state tax on Social Security in the 10 states that tax it, and then simulates annual withdrawals to see where the balance lands.
It depends on four things: how much you have saved, how much you spend per year, your investment return, and how much guaranteed income (Social Security, pension) covers your spending. A common planning benchmark is that savings supporting a 4 percent annual withdrawal rate typically last about 30 years. Lower returns, higher spending, or higher inflation shorten the runway. The calculator on this page runs the year-by-year math for your specific inputs.
The honest answer: no one knows the market or your lifespan. Retirement planners typically size the runway to age 95 as a safety buffer, because roughly one in four 65-year-olds today will reach 90 and one in ten will reach 95. If your runway ends before 95, the common moves are to save more now, delay Social Security to age 70, work part-time in early retirement, or lower your target spending. The calculator shows the gap in dollars so you can pick the lever.
As of 2026, the states that still tax at least some Social Security benefits are Colorado, Connecticut, Kansas, Minnesota, Montana, New Mexico, Rhode Island, Utah, Vermont, and West Virginia. Missouri and Nebraska have phased theirs out, and West Virginia is in the process of phasing theirs out through 2026. Rules vary widely by state, with most offering income-based exemptions that shield lower-income retirees. This calculator applies an approximate 5 to 10 percent haircut to Social Security in those states as a planning estimate. Check your state's current rules with a CPA for an exact number.
The most famous benchmark is the 4 percent rule, based on research by William Bengen in 1994. It says a retiree can withdraw 4 percent of the starting balance in year one, then adjust that dollar amount for inflation every year, and the portfolio has historically lasted 30 years in most scenarios. Modern research by Morningstar and others has suggested 3.3 to 4 percent depending on stock and bond valuations. Some planners prefer dynamic strategies like Guyton-Klinger, which flex withdrawals up or down based on portfolio performance.
Retiring earlier requires a larger nest egg because you need more years of income and a smaller Social Security benefit (claiming at 62 cuts your benefit roughly 30 percent below the benefit at full retirement age, while claiming at 70 adds roughly 24 to 32 percent). A common rule of thumb is that for every year you delay retirement past 62, you need about 5 to 8 percent less saved, because you contribute another year, your investments grow another year, your retirement is one year shorter, and your Social Security check is permanently higher. Run the calculator at each target age and compare the runway.
Disclaimer. This article is for educational purposes only and does not constitute legal, tax, accounting, or investment advice. We provide calculators and informational content, not investment or financial planning services. Retirement outcomes depend on market performance, life expectancy, tax laws, and individual circumstances. Consult a qualified financial planner or CPA for advice specific to your situation.