$
Total savings in 401k, IRA, and other accounts
Please enter your retirement balance.
$
How much you plan to withdraw each month
Please enter your monthly withdrawal.
%
Expected annual investment return (4–6% is typical for balanced portfolios)
Please enter a return rate (0–20%).
%
Inflation reduces purchasing power over time (2–3% is typical)
Please enter inflation rate (0–15%).
Your Savings Will Last Approximately
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⚠️ Note: This projection assumes a constant return rate and does not account for Social Security income, taxes on withdrawals, or market volatility. Real results will vary.
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Sources & Methodology
All calculations use verified financial formulas from authoritative sources. Updated March 2026.
Social Security Administration — Retirement Planner
Retirement income planning data and withdrawal benchmarks.
IRS — Retirement Plan Distributions
IRS guidance on retirement account withdrawals and tax implications.
Investopedia — The 4% Rule
Industry-standard retirement withdrawal rate methodology and research.
Methodology: Uses the present-value annuity formula: Years = -ln(1 - (Balance × r) / W) / ln(1+r), where r = monthly real return (nominal - inflation)/12 and W = monthly withdrawal. If real return ≥ 0, iterative month-by-month depletion is used for accuracy.
⏱ Last reviewed: March 2026
How Long Will Retirement Savings Last?
Whether your savings last 15 years or 35+ years depends on three factors: how much you have saved, how much you withdraw monthly, and what your investments earn. Getting the balance right is the foundation of retirement planning.
The Formula
Years = -ln(1 - (Balance × r) / W) ÷ ln(1 + r) ÷ 12
Where r = monthly real return rate (annual rate minus inflation, divided by 12) and W = monthly withdrawal. Example: $800,000 balance, $4,000/month withdrawal, 5% return, 3% inflation → real rate = 2%/12 → approximately 23 years.
The 4% Rule Explained
Financial researchers William Bengen and the Trinity Study found that withdrawing 4% of your portfolio annually (adjusted for inflation each year) made savings last 30+ years in 95% of historical market scenarios. On a $1 million portfolio, that's $40,000/year or $3,333/month.
Factors That Extend Retirement Savings
- Lower withdrawal rate: Even reducing from 5% to 4% annually can add 8–10 years to your runway.
- Social Security income: Average benefit of ~$1,900/month reduces how much you need to withdraw from savings.
- Part-time work: Earning $1,000–$2,000/month in early retirement dramatically reduces portfolio draws.
- Downsizing: Selling a family home and moving to a lower-cost area reduces both expenses and provides lump-sum cash.
- Annuities: Guaranteed income products ensure you never outlive a base income stream.
💡 Pro Tip — The 25× Rule: To retire comfortably, aim to save 25 times your annual expenses. If you spend $50,000/year, target a $1.25 million nest egg. This supports a 4% withdrawal rate indefinitely in most market conditions.
Frequently Asked Questions
With $500,000, a $2,000/month withdrawal, and a 5% annual return (3% inflation), your money lasts approximately 32 years. At $3,000/month, it lasts around 19 years. At $4,000/month — more than a 4% withdrawal rate — it depletes in about 13 years. Social Security income significantly reduces how much you need to withdraw.
The traditional 4% rule is widely accepted as a safe withdrawal rate for a 30-year retirement. Recent research suggests 3.3%–3.5% may be more conservative given lower expected future returns. Morningstar's 2023 research recommends 3.8% for a 90% success rate over 30 years. Flexible spending — reducing withdrawals in down markets — can significantly improve longevity.
The best approach: subtract your expected Social Security income from your monthly expenses, then enter only the gap as your monthly withdrawal. For example, if you need $4,500/month and Social Security pays $2,200, enter $2,300 as your withdrawal. This gives a more accurate picture of how long your personal savings need to last.
For planning purposes: a conservative balanced portfolio (60% stocks / 40% bonds) has historically returned 5–6% annually before inflation, or roughly 2–3% in real (inflation-adjusted) terms. More aggressive portfolios (80%+ stocks) may average 6–8%, but with higher volatility. Many planners recommend using 4–5% as a nominal return and 2–3% inflation for conservative projections.
Starting at age 73 (under SECURE 2.0), the IRS requires minimum withdrawals from traditional IRAs and 401(k)s. RMDs are calculated by dividing your account balance by your life expectancy factor. If your RMD exceeds your planned withdrawal, you must take the larger amount. RMDs can push you into a higher tax bracket — Roth IRA conversions before age 73 can help manage this.
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