Skip to main content
Your Retirement Number

The 25x Rule: Why Multiply Expenses by 25?

Pomegra Learn

The 25x Rule: Why Multiply Expenses by 25?

The 25x rule is the most widely adopted shorthand in retirement planning: accumulate 25 times your annual expenses and you can retire safely. It's simple, memorable, and has become the de facto retirement target across the financial independence community. Yet few people understand why that specific number works or what assumptions hide behind it.

Quick definition: The 25x rule states that if you save 25 times your annual expenses, you can withdraw 4% of that sum annually and not run out of money during a 30-year retirement with high statistical confidence.

The elegance of 25x is that it eliminates the need to think about withdrawal rates, market returns, or probability of success. Just save for 25 years at a 100% savings rate, or 50 years at 50% savings, and you've hit your number. In reality, the mathematics are far more nuanced—but the simplicity is the point.

Key takeaways​

  • The 25x rule is the mathematical inverse of the 4% safe withdrawal rate
  • It assumes a 30-year retirement horizon, a balanced stock/bond portfolio, and 3–4% inflation
  • The rule is conservative for young retirees (who might live 50+ years) and potentially aggressive for those with very high healthcare costs
  • Adjusting the multiple works: 20x for more aggressive investors, 30x for conservative ones
  • The rule has passed nearly 25 years of real-world testing since Fidelity popularized it

The mathematical foundation​

The 25x rule rests on one foundational equation:

Retirement Number = Annual Expenses × 25

Which is equivalent to:

Safe Withdrawal Amount = Retirement Number × 0.04 (4%)

Rearrange that:

Annual Expenses = Retirement Number × 0.04
Retirement Number = Annual Expenses / 0.04
Retirement Number = Annual Expenses × 25

So 25x is simply the algebraic rearrangement of a 4% withdrawal rate. If you believe a 4% rate is safe, then 25x follows automatically. The power of the number comes from nearly a century of retirement research suggesting that withdrawing 4% of your portfolio annually (adjusted upward for inflation) has a very high probability of lasting through a 30-year retirement. We'll explore that research in depth in the next article.

Why 25 years of savings matters less than you'd think​

One intuitive mistake: assuming 25x means you need 25 years of saving to reach retirement. This confuses the multiple with the timeline.

If you earn $100,000, spend $40,000, and save $60,000 annually, your retirement number is $40,000 × 25 = $1,000,000. At your savings rate, you reach that number in roughly 17 years (ignoring investment returns, which accelerate the timeline further). Someone earning $200,000 with $100,000 expenses saves $100,000 annually and hits the $2,500,000 number in 25 years—but they need to save $2.5 million, not reach it after exactly 25 years.

The key insight: your savings rate, not the calendar, determines when you hit your number. A person saving 50% of income reaches their 25x number faster than someone saving 20%, regardless of how many years pass.

The assumptions baked into 25x​

The 25x rule isn't universal truth—it's a rule of thumb based on specific assumptions. Understanding those assumptions tells you when the rule is reliable and when you need to adjust.

Assumption 1: 30-year retirement horizon​

The 4% rule was tested on 30-year retirement periods. A 65-year-old retiring until age 95 fits this window. Someone retiring at 45 (planning to age 95 or beyond) has a 50-year horizon. Someone retiring at 55 targeting age 100 has a 45-year horizon.

For longer retirements, a lower withdrawal rate is safer. Research suggests that for a 40-year horizon, a 3.3% rate might be more appropriate than 4%. This translates to needing 30x your expenses instead of 25x—a 20% larger number.

Assumption 2: A balanced portfolio​

The 4% rule and 25x rule assume a "balanced" portfolio: typically 60% stocks and 40% bonds, or similar mixes. This portfolio has historically delivered roughly 5–6% nominal annual returns over 30-year periods, with volatility that retirees can tolerate.

A portfolio of 100% bonds earning 3% annually could theoretically support only a 3% withdrawal rate (to preserve principal), requiring 33x your expenses. Conversely, a portfolio of 100% stocks earning 8% annually could support a 5–6% withdrawal rate, allowing just 17–20x your expenses—but only if you can tolerate 30%+ portfolio swings without panicking.

Assumption 3: Inflation at 2–3% annually​

The rule assumes prices rise by 2–3% annually on average. Most retirees increase their withdrawals each year by the inflation rate to maintain purchasing power. Over a 30-year period, this compounds significantly: an expense that costs $40,000 today costs roughly $76,000 in 20 years at 2.5% inflation.

The original 4% rule research used historical inflation data and tested against decades of market history. If you believe inflation will average 4% or more, the safe withdrawal rate drops further.

Assumption 4: Annual rebalancing and discipline​

The 25x rule assumes you stick to your plan: withdrawing exactly 4% of your starting balance annually (adjusted for inflation), rebalancing your portfolio yearly, and not panic-selling during market crashes. Many retirees fail here. During the 2008 financial crisis, some retirees stopped withdrawals entirely (locking in losses) or sold stocks at the worst time (buying high, selling low). This behavioral failure turned a conservative plan into a dangerous one.

Adjusting the multiple for your situation​

The 25x rule is a useful starting point, but you can and should adjust it based on your circumstances.

More aggressive: 20x rule​

If you're retiring at 65 with a 25–30 year retirement horizon, have a high risk tolerance, maintain a portfolio weighted 70%+ toward stocks historically earning 6%+, and can tolerate seeing your portfolio drop 40% in a bear market, a 20x multiple might work.

A person with $60,000 annual expenses and a 20x target needs $1,200,000 instead of $1,500,000—a meaningful difference. This assumes a 5% withdrawal rate. The higher return expectations of stocks provide the buffer.

Example: Robert, 66, has a $60,000 annual budget, a $1.2 million portfolio (60% stocks, 40% bonds, expected 5.2% return), and high confidence in a 30-year horizon. His first-year withdrawal is $60,000 (5%). The math works, but he must endure occasional 35%+ portfolio declines without second-guessing the plan.

More conservative: 30x rule​

If you're retiring early (before 60), have a very long retirement horizon, face significant healthcare uncertainties, or prefer greater psychological comfort with a margin of safety, a 30x multiple may be appropriate.

A $60,000 annual budget requires $1,800,000 at 30x, compared to $1,500,000 at 25x. The additional $300,000 provides a cushion. At 3.3% withdrawal rate, there's more breathing room for market volatility, unexpected expenses, or lifestyle inflation.

Example: Jennifer, 45, plans to retire immediately and live to 95+, needs $50,000 annually, and values peace of mind over optimal growth. Her 30x target is $1,500,000. If she accumulates $1,500,000 by age 50, she can confidently retire for 45 years, even through severe market downturns.

The 25x rule across different life stages​

Retiring in your 30s or 40s: aim higher​

The FIRE (Financial Independence, Retire Early) community often pursues early retirement in their 30s or 40s, which requires 50+ year horizons. Standard 25x often isn't conservative enough for someone retiring at 35 planning to age 90+. A 30x or even 35x target is more prudent.

Someone with $40,000 annual expenses targeting FIRE might accumulate $1.4 million (35x) instead of $1 million (25x). This larger number provides insurance against inflation, sequence-of-returns risk, and the genuine uncertainty of maintaining the same spending for 55 years.

Retiring at 65: 25x works well​

A 65-year-old with a traditional life expectancy of 85–90 fits the original 25x research perfectly. It's the sweet spot where the rule was validated. Less anxiety about fitting the rule, more confidence in the historical evidence.

Retiring in your 50s: 28–30x is safer​

The 50-something retiree has a longer horizon than 65 (perhaps 35–40 years) but not as extreme as a 35-year-old FIRE follower. A 28x–30x target is reasonable: enough safety margin without being overly conservative.

The role of sequence of returns risk​

The 25x rule assumes that withdrawals happen smoothly over 30 years. In reality, market returns are lumpy. The order of returns matters enormously.

How sequence risk affects retirement​

Imagine two portfolios, each earning 5% on average over 10 years, but one starts with three bad years (−15%, −10%, −8%) and the other starts with three great years (+25%, +20%, +15%). A retiree taking 4% withdrawals annually from the first portfolio is withdrawing from a shrinking base when returns are worst—this is dangerous. The second retiree sells from a growing base during gains—much safer.

This is called sequence-of-returns risk, and it's one reason the 4% rule includes a large safety margin. The rule was tested against the worst historical market periods (including the Great Depression) to ensure robustness even when returns arrive out of order.

Real-world examples​

Alice, 32, targeting age 95

Alice spends $45,000 annually and wants to retire at 35. Her 50-year horizon justifies a 32x target: $45,000 × 32 = $1,440,000. She's accumulated $400,000 by age 30 and saves $50,000 annually. At 6% investment returns, she'll hit $1,440,000 around age 36. Early retirement is on track.

David, 58, with a pension

David will receive a $30,000 annual pension starting at 62. His total annual needs are $70,000, but his investments only need to cover $40,000 (the gap) once the pension kicks in. Using 25x for just his gap expenses: $40,000 × 25 = $1,000,000. He has $800,000 accumulated and 4 years until his pension starts, so he's slightly behind—but the pension reduces his required portfolio size, putting him within striking distance.

Elena, 66, very conservative

Elena has $1,500,000 accumulated and spends $50,000 annually. By the 30x rule, she'd need only $1,500,000, so she hits her conservative target exactly. This gives her enormous peace of mind. She can afford to be passive, spend modestly, and weather any market downturn.

Common mistakes​

Mistake 1: Assuming 25x is gospel The 25x rule works for many people, but it's a generalization. A 45-year-old retiree needs more than 25x (longer horizon). Someone with high healthcare risks or dependents may need 30x+. Don't blindly follow 25x without considering your personal situation, expected lifespan, and risk tolerance.

Mistake 2: Forgetting that 25x is based on historical market performance The 4% rule and 25x are grounded in historical stock and bond returns (roughly 5–6% nominal for balanced portfolios). If markets deliver lower future returns—say 4% instead of 6%—the safe withdrawal rate drops and your number should rise. Equally, if bonds drop to 1% yields, the traditional 60/40 portfolio's return expectations decline, weakening the case for 25x.

Mistake 3: Ignoring your portfolio's actual composition If you're invested 100% in bonds earning 2%, you don't have a 4% withdrawal rate—you can only safely withdraw 2%. If your portfolio is 90% stocks and you panic-sell during crashes, you're not following a disciplined 4% plan. Your actual safe withdrawal rate depends on your actual portfolio and your actual behavior, not on your stated allocation.

Mistake 4: Confusing 25x with a savings timeline Some people think 25x means you need 25 years of savings. This conflates the multiple with the timeframe. Your timeline depends on your savings rate and investment returns, not on the size of the multiple. A high-saving person hits their 25x number faster than a low-saving person, regardless of the multiplier.

Mistake 5: Adjusting 25x in the wrong direction Some retirees see their portfolio grow to 30x or 40x and think they've "overshot" their target, so they spend more. Others reach only 20x and think they're undershooting. The truth is more subtle: if you reach 25x with your actual portfolio composition and behavior patterns, you're at the target. Exceeding 25x provides extra safety, not a license to spend more.

FAQ​

If I have a very long time horizon (age 30, retiring at 45), should I use 40x or 50x?​

Research on sustainable withdrawal rates for 50-year horizons suggests a 3% rate, which translates to 33x. A conservative person might target 35–40x. This isn't an arbitrary jump—it reflects the mathematical reality that longer retirements carry greater inflation risk and sequence risk. A 30x–35x target is reasonable for a 45-year-old.

Should I adjust 25x for my expected Social Security income?​

Yes. If you'll receive $25,000 annually from Social Security, you only need your portfolio to generate the gap—say, $40,000 if your total needs are $65,000. Using 25x on just that gap: $40,000 × 25 = $1,000,000. You don't need to build a portfolio that supports your full $65,000 need; Social Security covers part of it.

What if I retire during a market crash? Is 25x still safe?​

This is sequence risk. If you retire with a $1,000,000 portfolio in October 2008 and immediately start taking 4% ($40,000), you're withdrawing from a portfolio that might drop 40% by March 2009—reducing it to $600,000. Taking withdrawals while the portfolio is shrinking is dangerous. A retiree in this position should reduce withdrawals temporarily, cut expenses, or tap other assets until markets recover. The 25x rule assumes normal markets, not the worst possible timing.

Can I use 25x if I'm still working part-time in retirement?​

Yes. If you plan to earn $20,000 annually from part-time work, you only need your investments to cover the remaining expenses. A $60,000 total need minus $20,000 earned income means your portfolio only needs to support $40,000: $40,000 × 25 = $1,000,000 instead of $1,500,000.

Is 25x enough if I expect significant healthcare costs?​

Standard 25x estimates typically include healthcare, but if you face unusual expenses—chronic illness, long-term care, supporting dependents—add a buffer. Many financial advisors suggest 30x for conservative healthcare estimates. Alternatively, some retirees set aside a separate "healthcare fund" outside the 25x calculation.

How does inflation adjustment work with 25x?​

The 4% withdrawal rate (which underlies 25x) assumes you increase your withdrawal by inflation each year. A first-year $40,000 withdrawal becomes $41,000 if inflation is 2.5%. Over 30 years, these compounding increases mean you're withdrawing more in absolute dollars, even though purchasing power remains flat. This is built into the original 4% research, so 25x inherently accounts for inflation.

Summary​

The 25x rule is the inverse of the 4% safe withdrawal rate: accumulate 25 times your annual expenses and you can withdraw 4% annually (adjusted for inflation) and reliably retire for 30 years. The rule works well for 65-year-old retirees with balanced portfolios and modest healthcare risks, but it should be adjusted—higher for longer retirements or conservative personalities, lower for shorter horizons or risk-tolerant investors. Understanding the assumptions behind 25x allows you to customize the rule to your life rather than blindly following a generic target.

Next​

→ The 4% Rule Explained