Retirement Calculator

Safe Withdrawal Rate Simulator: What It Calculates and How to Read the Result

Reviewed by Raman Singh, CFP® · IRS Enrolled AgentUpdated

Quick answer

A safe withdrawal rate simulator tests your proposed initial withdrawal percentage against historical or modeled market sequences to estimate the probability your portfolio survives a 30-year retirement. The classic 4% rule is a reference point, not a rule — most current research suggests 3.5–3.8% for today's valuation environment, or higher (4.5–5%) if you have meaningful spending flexibility.

Safe Withdrawal Rate Simulator
A sequence-of-returns lens on retirement withdrawals. Explore how different spending rules behave across history (and bootstrap Monte Carlo).

What SWR is: a planning stress-test for how long a portfolio might fund withdrawals under different market sequences.

What SWR is not: a guarantee. Real life includes taxes, spending flexibility, one-time events, healthcare costs, and changing allocations.

1) Household & timeline
Set ages and planning horizon.

Locks retirement start age to current age.

2) Portfolio assumptions
Allocation, fees, inflation.
Stocks60%
Bonds40%

Annual returns use US stocks + 10y US bonds; rebalanced annually.

3) Strategy
Choose a withdrawal rule for the detailed view.

Used when rate choice is Custom.

Default: ON

4) Simulation engine
Historical rolling periods (recommended) or Monte Carlo.

Used to compute a suggested initial withdrawal rate for the active scenario.

Success rate
100.0%
Median ending portfolio
$12.1M
Worst-case (5th percentile) ending
$6.2M
Median max drawdown
-24.3%
Median avg withdrawal
$114.3K
Suggested initial SWR
5.30%
You’re in a solid range, and we can make it resilient.
Even good projections benefit from a tax-aware, sequence-aware plan and a clear withdrawal or conversion strategy.
  • Success probability: 100%
  • Small assumption changes can materially change outcomes.
  • A coordinated plan can reduce risk and improve efficiency.

Schedule a Strategic Fit Interview to confirm you’re optimized and protected against downside scenarios.

Schedule a Strategic Fit Interview

No commitment. No sales agenda. 30 minutes with a flat-fee CFP & Enrolled Agent.

Scenario comparison (up to 3)
Compare success + downside across strategies under the same market sequences.
Static 3.5%
Static 3.5%

Annual

This is the active scenario. Edit its strategy settings in the left-side Strategy panel.
Static 4.0%
Static 4.0%

Annual

This card controls a comparison scenario. The detailed charts below reflect the selected scenario.
Guardrails
Guardrails 4.0%

Blocks raises

Annual

This card controls a comparison scenario. The detailed charts below reflect the selected scenario.
ScenarioSuccessMedian ending5th pct endingMedian max DDMedian avg wd
Static 3.5%100.0%$12.1M$6.2M-24.3%$114.3K
Static 4.0%100.0%$9.9M$5.0M-25.0%$130.6K
Guardrails100.0%$8.6M$4.9M-27.2%$167.6K
Portfolio balance over time
Median with 5th–95th percentile band.
Withdrawals over time
Shows dynamic adjustments clearly (median + band).
Failure distribution
When failures happen (age at end-of-year depletion).
No failures in the simulated runs.
Year-by-year table (representative run)
Shows the run closest to the median ending balance.
AgeYearStartWithdrawalStock rBond rFeesEndNote
601962$1,500,000$0-8.8%5.7%$7,274$1,447,576
611963$1,447,576$022.6%1.7%$8,268$1,645,413
621964$1,645,413$016.4%3.7%$9,160$1,822,909
631965$1,822,909$012.4%0.7%$9,819$1,953,964
641966$1,953,964$0-10.0%2.9%$9,299$1,850,523
651967$1,850,523$64,76823.8%-1.6%$10,147$2,019,327
661968$2,019,327$66,38810.8%3.3%$10,526$2,094,626
671969$2,094,626$68,047-8.2%-5.0%$9,429$1,876,343
681970$1,876,343$69,7483.6%16.8%$9,831$1,956,394
691971$1,956,394$71,49214.2%9.8%$10,598$2,108,937
701972$2,108,937$73,27918.8%2.8%$11,439$2,276,315
711973$2,276,315$75,111-14.3%3.7%$10,222$2,034,212
721974$2,034,212$76,989-25.9%2.0%$8,343$1,660,306
731975$1,660,306$78,91437.0%3.6%$9,776$1,945,520
741976$1,945,520$80,88723.8%16.0%$11,252$2,239,174
751977$2,239,174$82,909-7.0%1.3%$10,385$2,066,702
761978$2,066,702$84,9826.5%-0.8%$10,265$2,042,678
771979$2,042,678$87,10618.5%0.7%$10,891$2,167,226
781980$2,167,226$89,28431.7%-3.0%$12,244$2,436,569
791981$2,436,569$91,516-4.7%8.2%$11,779$2,344,061
801982$2,344,061$93,80420.4%32.8%$14,106$2,807,176
811983$2,807,176$96,14922.3%3.2%$15,546$3,093,569
821984$3,093,569$98,5536.2%13.7%$16,350$3,253,669
831985$3,253,669$101,01631.2%25.7%$20,339$4,047,465
841986$4,047,465$103,54218.5%24.3%$23,822$4,740,674
851987$4,740,674$106,1305.8%-5.0%$23,521$4,680,633
861988$4,680,633$108,78416.5%8.2%$25,879$5,150,003
871989$5,150,003$111,50331.5%17.7%$31,733$6,314,962
881990$6,314,962$114,291-3.1%6.2%$31,208$6,210,388
891991$6,210,388$117,14830.2%15.0%$37,820$7,526,206
901992$7,526,206$120,0777.5%9.4%$40,081$7,976,165
911993$7,976,165$123,07910.0%14.2%$43,846$8,725,381
921994$8,725,381$126,1561.3%-8.0%$41,956$8,349,340
931995$8,349,340$129,31037.2%23.5%$54,134$10,772,632
941996$10,772,632$132,54222.7%1.4%$60,744$12,088,110

Disclosures
Educational only (hypothetical modeling).

This simulator is for educational purposes only and is not investment, tax, or legal advice.

Results are hypothetical and highly sensitive to return sequence, fees, inflation, and spending behavior. Past performance does not guarantee future results.

If you’d like a plan tailored to your household, taxes, and account structure, consider scheduling a consultation.

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What This Calculator Actually Answers

This simulator tests your proposed withdrawal rate (an initial dollar amount as a percentage of starting portfolio, then adjusted for inflation each year) against thousands of randomized or historical market sequences. The output is a probability distribution of outcomes: in what percentage of trials does your portfolio survive 30 years? At what age does the median failing trial run out?

Crucially, the tool also models 'dynamic' withdrawal strategies — variations on the static 4% inflation-adjusted rule that allow modest spending cuts in down years. Dynamic strategies consistently outperform static ones in stress-tested simulations.

How to Read the Result

The headline success rate is less important than two related numbers: the percentage of trials that fail before age 85, and the 10th-percentile ending balance. A plan with 90% success but a 10th-percentile ending balance near zero is fragile; a plan with 80% success but a 10th-percentile ending balance of $500K+ is durable in ways the success-rate alone doesn't show.

Pay attention to the difference between static and dynamic withdrawal results. If switching from static-4% to a dynamic strategy improves success from 85% to 95%, that signals your plan benefits a lot from spending flexibility — which is a real planning insight, not just a number.

Common Mistakes

  • Treating the success rate as a guarantee. An 85% success rate means 15% of historical (or modeled) sequences failed — and 'failure' is portfolio depletion before age 95, which is a genuine outcome.
  • Using a static 4% rule when you actually have spending flexibility. Real retirees almost never spend at a fixed inflation-adjusted rate through a bear market; modeling that flexibility raises the realistic safe rate meaningfully.
  • Ignoring Social Security and pension income. These are part of the spending solution and reduce the load on the portfolio.
  • Using historical U.S. returns without acknowledging that future returns may differ materially — and that high current equity valuations argue for lower withdrawal rates.
  • Not stress-testing the worst 10% of outcomes. A plan that works in 90% of scenarios still needs a defensive plan for the 10% it doesn't.

When This Calculator Is Not the Right Tool

This is a portfolio durability tool, not a tax-coordination tool. It answers 'will my money last?' under various assumptions; it does not answer 'how should I draw from each account type?' or 'should I do Roth conversions?' Use this in tandem with the tax-coordination tools, not as a substitute for them.

Frequently Asked Questions

Does the 4% rule still work?

Sort of — but with caveats. The original 4% rule was derived from U.S. historical data with a 30-year horizon. It remains a useful reference point. Recent research (Pfau, Kitces) suggests 3.5–3.8% is a more defensible static rate in today's valuation environment, while dynamic strategies (variable withdrawals, guardrails) can sustainably support 4.5–5%+ with meaningful spending flexibility.

What's a 'guardrails' withdrawal strategy?

Guardrails set upper and lower thresholds on your portfolio value, with predefined rules for when to cut spending (when portfolio falls below the lower guardrail) or increase spending (when it rises above the upper guardrail). Compared to static withdrawals, guardrails capture upside in good markets and protect the portfolio in bad ones — and consistently outperform static strategies in stress tests.

How does my asset allocation affect the safe withdrawal rate?

Heavily. A 100% bond portfolio has a much lower safe withdrawal rate (often 3% or less) than a 60/40 stock/bond portfolio (4%+). The reason is that bond-only portfolios cannot keep pace with inflation over a 30-year horizon. Most successful retirement plans hold 50–70% equity even at retirement age.

What if I'm planning for a longer horizon than 30 years?

Safe rates need to be lower. A 40-year horizon (retiring at 55 or 60 with longevity expectations) typically supports closer to 3% as the static rate. The compounding effect of small differences over four decades is dramatic.

Calculators are a starting point. If you want to see how the result applies to your specific situation across tax brackets, IRMAA thresholds, and your full retirement income plan, schedule a 20-minute Strategic Fit Interview.