Will the portfolio outlive you, or the other way around?
Enter what you have, what you'll spend, and what Social Security will cover. The calculator runs the simple-average path year-by-year and shows either how much is left at age 100, or which year the well runs dry — in today's dollars, so the numbers stay legible.
Year-by-year trajectory
Read each row left to right: Social Security pays what it pays, your investments fill in the rest, and together they fund your spending. Balance left is what's still working for you next year. All in today's dollars.Estimates only. Constant return + constant inflation; the calculator runs the average path, not a Monte Carlo. Real markets are lumpy — early bear years are far worse than late ones (sequence-of-returns risk), so a path that "lasts 30 years" on average may not last 30 years if the first five are bad. Pre-retirement contributions are applied at year-end and grow at the step-up rate you set; contributions stop the year retirement starts. Social Security uses FRA 67 (everyone born 1960+); claim-age adjustments follow SSA's published reduction/credit rules — if your FRA is 66, the early-claim cuts are slightly smaller than shown. Withdrawal taxes (Traditional 401(k), SS above modest thresholds) aren't modeled — if your portfolio is mostly pre-tax, plan on a 15–25% haircut to the headline. The calculator also doesn't model: required minimum distributions starting at age 73 (born 1951–59) or 75 (born 1960+), the pre-Medicare insurance gap if you retire before 65 ($700–1,500/mo per person on the ACA marketplace), pensions, spousal/survivor Social Security, part-time income, or rental income — offset your annual spending manually if any of these apply. Use this for direction-finding, not for picking a precise retirement date.
Spend numbers stay in today's dollars.
A "$60,000/year retirement" twenty years from now is not $60,000 of today's groceries — it'd be ~$110,000 of nominal dollars to buy the same cart. The calculator keeps the spending box in today's dollars and inflates internally, so the headline numbers stay comparable to your current paycheck.
- Real return ≈ return − inflation. What actually grows your purchasing power. A 6.5% nominal return with 3% inflation is ~3.4% real growth — your money is doubling every ~21 years in real terms, not 11.
- SS has COLA. Social Security adjusts annually for inflation, so its real value is roughly stable. The calculator treats your benefit input as today's dollars and inflates it forward.
- Pre-tax vs. post-tax. Withdrawals from Traditional 401(k)s/IRAs are taxed as ordinary income. Roth withdrawals aren't. Your "$60,000 spend" should be the gross number — what hits your account before taxes — if most of your savings is Traditional. See the Roth vs. Traditional guide for the tax-timing detail.
Think of the portfolio as a bucket leaking at a constant rate. SS is a small refill that turns on at age 62–70. The question is whether the bucket can keep up with the leak until you don't need it anymore.
Every dollar of SS is one less from the portfolio.
Social Security and portfolio withdrawals fund the same spending — they just trade off. If you spend $60k and SS covers $24k, the portfolio only has to produce $36k. That's the lever delaying SS pulls: the longer you wait (up to age 70), the bigger SS is, and the smaller the portfolio draw stays for the rest of your life.
- Claiming early at 62 cuts your benefit by roughly 30% versus your Full Retirement Age (66–67 for most people).
- Claiming at FRA gives you 100% of your earned benefit — the baseline number on your SSA statement.
- Delaying past FRA to age 70 earns 8% per year in delayed retirement credits — about 24% more than your FRA amount.
- The break-even age for delaying is usually mid-80s. If you live longer than that, delaying wins by a lot. If you don't, claiming early wins.
The full picture is in the Social Security guide.
A starting rate, not a guarantee.
The "4% rule" came from a 1994 study (Bengen) showing that a portfolio could sustain a 4% initial withdrawal — adjusted upward for inflation each year — through any 30-year retirement window in U.S. history. It's a useful starting heuristic, not a law. It assumed a 50/50 stock/bond mix, U.S.-only data, and a fixed 30-year horizon.
- Sequence of returns matters more than the average. A bad first decade can sink a "safe" plan; a good first decade can rescue an aggressive one.
- Flexible spending raises the safe rate. If you'll cut back in bad years, you can start higher (4.5–5%). If your spending is fixed (debt, healthcare floor), start lower (3.5%).
- Longer horizons need lower rates. A 40+ year retirement (FIRE) typically uses ~3.25–3.5% as the durable rate.
- This calculator runs the average path. It won't show sequence risk — for that, look at Monte Carlo tools (e.g. ficalc.app) once your direction is set here.
What this calculator doesn't model.
- Sequence-of-returns risk. Constant 6.5% looks fine on paper. Real markets compress 6.5% out of years like −20%, +28%, +5%, −10% — and the order of those years matters enormously in the early withdrawal phase.
- Taxes on withdrawals. Traditional 401(k)/IRA withdrawals add to ordinary income; SS is partially taxed; Roth is not. Your "spend" needs to include whatever taxes you'll owe.
- Healthcare cost shock. Long-term care can run $100k+/yr. A small annual reserve doesn't cover it; that's a separate insurance/family conversation.
- Pensions, annuities, RMDs. Not modeled. RMDs (Required Minimum Distributions) start at age 73–75 from Traditional accounts and may force larger withdrawals than you wanted, with tax consequences.
- Spousal benefits. If married, your SS strategy interacts with your spouse's. The rules are worth a planner conversation if the dollars are large.