Retirement Income Sustainability Calculator
The central question in retirement planning: will my savings last? Enter your portfolio balance, annual spending goal, and Social Security income. The calculator projects your portfolio balance year by year — in today's dollars — across three return scenarios so you can see how sensitive your plan is to investment performance.
How to read your results
Withdrawal rate: the key number
Your withdrawal rate is the annual net portfolio draw (spending minus guaranteed income) divided by your starting portfolio. Research by William Bengen (1994) and the Trinity Study (1998) established historical benchmarks for a 30-year retirement with a 50/50 stock-bond portfolio:12
| Net withdrawal rate | Historical 30-year success | Interpretation |
|---|---|---|
| ≤ 3% | ~100% | Very conservative — survives worst historical sequences |
| 3–4% | 95–100% | The research zone — historically safe for 30 years |
| 4–5% | 80–95% | Borderline for 30-year horizons; less so for 20-year |
| 5–6% | 60–80% | Elevated risk, especially for 30–40-year retirements |
| ≥ 6% | < 60% | High risk — plan modification likely necessary |
Important: these success rates apply to a fixed, inflation-adjusted withdrawal strategy. If you can reduce spending by even 10% in a bad market year, your odds of success improve substantially. This is the logic behind Guyton-Klinger guardrail rules, which allow higher initial withdrawals in exchange for spending flexibility.
Why Social Security income changes everything
SS income reduces your net portfolio draw dollar for dollar. A couple receiving $48,000/year in combined SS benefits at age 70 has the equivalent of $1.2 million in guaranteed lifetime income at a 4% withdrawal rate — income that doesn't depend on market performance. This is why delaying SS to 70 is arguably the most powerful portfolio-preservation tool available to most retirees. See our Social Security Claiming Strategy Guide for the break-even math.
Return rates in the projection
The three scenarios use real (after-inflation) annual returns, so all dollar amounts stay in today's terms:
- Conservative (3% real) — approximately consistent with a mostly-bond or income-tilted portfolio. Can be squeezed in low-yield environments.
- Moderate (4.5% real) — historically consistent with a balanced 60/40 stock-bond portfolio over long periods. A common baseline assumption for diversified retiree portfolios.3
- Growth (6% real) — consistent with an equity-heavy allocation (70–80% stocks). Higher potential return carries higher sequence-of-returns risk in the early years.
Three risks this model doesn't capture
1. Sequence-of-returns risk
A bad first decade can permanently impair a retirement portfolio even when long-run average returns match your assumption. Two retirees with identical $1.2M starting portfolios and the same 5% long-run average can end up with portfolios differing by over $300,000 depending on when the bad years land. The projection above shows the average case. It doesn't show the bottom quartile of outcomes. See our sequence of returns risk guide for the full analysis and five hedging strategies.
2. Inflation variability
This calculator removes inflation from both sides by using real returns and constant real spending. But real-world inflation isn't constant, and retiree-specific expenses — particularly healthcare — inflate faster than CPI. Healthcare costs have averaged approximately 5–6% annual inflation over the past 20 years, meaning their real cost rises against a "constant real spending" assumption. A retiree spending $12,000/year on healthcare today could face $21,000 in real costs 20 years from now if that differential holds.
3. Lumpy, unpredictable expenses
Major home repairs, new vehicles, helping adult children, and especially long-term care costs do not appear in a steady annual spending figure. The median cost of assisted living is approximately $65,000/year (2026 national median); memory care and skilled nursing average $100,000–$140,000/year in most markets. A realistic retirement income plan includes explicit reserves or insurance for low-probability, high-cost events — not just average annual spending.
What a retirement income specialist actually models
The projection above is a useful starting frame. A retirement income advisor goes several levels deeper:
- Account-by-account sequencing — which accounts to draw from in what order, year by year (taxable first, then IRA, Roth last), to minimize lifetime tax cost. See our withdrawal order guide.
- Roth conversion strategy — filling your current tax bracket each year in the pre-RMD window to prevent the "RMD tax bomb" in your 70s. Our Roth conversion guide has the worked numbers.
- IRMAA management — structuring distributions to stay below Medicare IRMAA surcharge tiers, which can add $974–$6,936/year per household to Medicare costs. Details in our IRMAA planning guide.
- Social Security optimization — claiming timing, couples coordination, and the bridge-to-70 strategy to maximize lifetime SS income and survivor benefits.
- Sequence-of-returns hedging — whether a bucket strategy, bond tent, or partial income annuity makes sense as a first-decade cushion to protect against early losses.
- Monte Carlo simulation — testing the plan against thousands of historical and randomized return sequences to show the distribution of outcomes, not just the average case.
Get your scenario modeled with real numbers
The calculator above uses averages. A fee-only retirement income specialist runs your actual scenario — your accounts, Social Security records, RMD schedule, and tax situation — to build a year-by-year income plan that's built to survive, not just pass an average-case projection.
Related guides and tools
- Safe Withdrawal Rate Guide — the 4% rule, historical success rates, and Guyton-Klinger guardrails
- Sequence of Returns Risk — why the timing of returns matters more than the average
- Social Security Claiming Strategy — break-even math and couples coordination for maximum lifetime income
- Retirement Bucket Strategy — three-bucket model for managing sequence risk and spending discipline
- Tax-Efficient Withdrawal Order — account sequencing that saves tens of thousands in avoidable taxes
- Roth Conversion Window Guide — pre-RMD bracket arbitrage to reduce future tax burden
- Social Security Timing Calculator — model claiming at 62 vs. 70
- Bengen, W.P. (1994). "Determining Withdrawal Rates Using Historical Data." Journal of Financial Planning. Original research establishing the 4% safe withdrawal rate guideline based on U.S. historical market data 1926–1993. FPA Journal.
- Cooley, P.L., Hubbard, C.M., & Walz, D.T. (1998). "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable." AAII Journal. The Trinity Study — confirmed the 4% guideline across multiple asset allocations and historical periods, establishing the success-rate framework used in this calculator.
- Vanguard (2024). "Vanguard Capital Markets Model." Long-run expected real returns for a balanced 60/40 portfolio. See Vanguard retirement resources. Historical 60/40 real returns have approximated 4–5% over multi-decade periods.
- Pfau, W. & Kitces, M. (2014). "Reducing Retirement Risk with a Rising Equity Glidepath." Journal of Financial Planning. Research on sequence risk and optimal asset allocation through retirement. Available at Kitces.com.
Withdrawal rate success rates reflect historical U.S. market data; past performance does not guarantee future results. Calculator uses constant real return assumptions — not Monte Carlo simulation. Return assumptions and research benchmarks verified April 2026. No regulatory values (tax brackets, IRS limits) are used in this calculator.