How to Build a Retirement Savings Plan: A Data-Driven Guide to Investment Growth Milestones by Age

Why Most Americans Are Behind on Retirement Savings

The gap between where Americans are and where they need to be for retirement is staggering. According to the Federal Reserve's 2022 Survey of Consumer Finances—the most comprehensive household wealth survey conducted in the United States—the median retirement account balance across all American families is just $87,000. The average is $333,940, but that figure is pulled dramatically upward by a small number of very wealthy households. For most families, retirement savings fall far short of what financial planners consider adequate.[1]

The Federal Reserve's 2024 Survey of Household Economics and Decisionmaking (SHED) paints an even more sobering picture of how Americans perceive their own readiness. Only 35% of non-retired adults say their retirement savings plan is "on track," down from 39% in 2021. Meanwhile, 67% of adults report having some form of retirement asset, meaning a full third of the population has no dedicated retirement savings at all. Among younger adults aged 18 to 29, just 23% believe they are on track—a figure that should serve as a wake-up call for an entire generation.[2]

The 2025 EBRI/Greenwald Retirement Confidence Survey, conducted among 2,767 Americans, found that 67% of workers express confidence in having enough money for a comfortable retirement. Yet that headline masks deeper anxiety: seven in ten workers worry that rising living costs will prevent them from saving enough, and more than half say healthcare expenses are already hurting their ability to set money aside. Confidence and preparedness are not the same thing. Many workers feel optimistic about retirement in the abstract but have not calculated a specific savings target or checked whether their current trajectory will get them there.[3]

The good news is that compound growth rewards even modest, late-starting contributions far more than most people expect. The purpose of this guide is not to induce panic but to give you a concrete framework: a specific retirement number, age-based milestones to measure your progress, and actionable strategies whether you are 25 and just starting or 50 and playing catch-up. Every decade of saving matters, and the math consistently shows that the best time to start was yesterday—the second-best time is today.

How to Calculate Your Retirement Number: The 4% Rule and the Rule of 25

Your "retirement number" is the total portfolio value that, once reached, can sustain your desired lifestyle without running out of money. The most widely used framework for determining this number comes from financial planner William Bengen, who in 1994 analyzed every 30-year period in U.S. stock and bond market history going back to 1926. His finding: a retiree who withdrew 4% of their portfolio in the first year of retirement, then adjusted that dollar amount for inflation each subsequent year, never ran out of money in any historical period. This became known as the "4% rule," and the corresponding savings target is simply your annual spending divided by 0.04—or equivalently, your annual spending multiplied by 25.[16]

Here is the math in practice. If you estimate needing $60,000 per year in retirement spending (in today's dollars), your target portfolio is $60,000 × 25 = $1,500,000. If you plan to spend $80,000 per year, you need $2,000,000. If you expect Social Security to cover $24,000 of your annual expenses, only the remaining $36,000 needs to come from your portfolio, reducing your target to $36,000 × 25 = $900,000. The Rule of 25 gives you a concrete number to aim for—and a number you can track against the milestones we will discuss in the next section.

Morningstar's 2026 retirement income research, led by Christine Benz, updates Bengen's original work with current capital markets assumptions. Their analysis finds that the highest safe starting withdrawal rate for a retiree seeking a 90% probability of funds lasting 30 years is 3.9%—up from 3.7% in their 2024 study, thanks in part to higher bond yields. For a more conservative planner or someone expecting a longer retirement (say, retiring at 55 and planning for 40+ years), Morningstar and Vanguard suggest 3.3% to 3.5% may be more appropriate. In other words, early retirees should consider the Rule of 28 to 30 instead of the Rule of 25.[16]

One critical nuance the 4% rule does not capture is sequence-of-returns risk: the danger that a major market decline in the first few years of retirement forces you to sell assets at depressed prices, permanently depleting your portfolio even if markets recover later. A retiree who enters a bear market in year one faces far worse odds than one who encounters the same bear market in year fifteen, even if both experience identical average returns over 30 years. This is why many advisors recommend keeping one to two years of living expenses in cash or short-term bonds at retirement, so you never have to sell equities at a loss to cover bills. The SEC's investor education tools and the CFPB's retirement planning resources offer calculators and worksheets that help model these scenarios for your specific situation.[10, 12]

Retirement Savings Milestones by Age: The Benchmarks That Actually Matter

Fidelity Investments' retirement savings guidelines are among the most widely cited benchmarks in personal finance, and for good reason: they are derived from thousands of Monte Carlo simulations using historical market data, calibrated to achieve a 90% probability of success. The core guideline says you should aim to have saved roughly 1× your annual salary by age 30, 3× by 40, 6× by 50, 8× by 60, and 10× by 67 (Fidelity's assumed retirement age). These multipliers assume you begin saving 15% of your income annually (including any employer match) starting at age 25, invest in an age-appropriate mix of stocks and bonds, and target replacing about 45% of your pre-retirement income from savings alone (the rest coming from Social Security).[17]

How do these benchmarks compare to reality? The actual savings data from Fidelity and the Federal Reserve's SCF tell a very different story. The average retirement account balance for Americans under 35 is roughly $49,000—which might sound reasonable until you note that the median for this age group is substantially lower, since averages are skewed by high savers. For ages 35 to 44, the average climbs to about $142,000; for ages 45 to 54, approximately $313,000; for 55 to 64, about $538,000; and for 65 to 74, roughly $609,000. At every age bracket, the average falls well below the Fidelity benchmark for someone earning the median household income of approximately $80,000.[18, 1]

To make these benchmarks personal, multiply your current gross annual salary by the target multiple for your age. If you earn $75,000 and are 40 years old, the Fidelity guideline suggests having $225,000 saved for retirement (3× $75,000). If you are at $150,000 instead, you are ahead of schedule—use the extra runway to either retire earlier or aim for a higher spending level in retirement. If you are behind, do not despair. The milestones accelerate from 3× at 40 to 6× at 50, which means the decade of your 40s is where aggressive saving and compounding produce the most dramatic leap. This is also the decade where many workers reach their peak earnings, making higher savings rates possible precisely when they matter most.

Keep in mind that these benchmarks are guidelines, not rules carved in stone. Your personal retirement number depends on two variables: when you plan to retire and how much you plan to spend. Fidelity's own research notes that someone planning to retire at 65 rather than 67 should aim for roughly 12× their salary, while someone willing to work until 70 may need only 8×. Similarly, if you live in a high-cost city or expect significant healthcare expenses, you may need 12×-15× salary regardless of retirement age. The multiplier framework is a starting point—but it is a far better starting point than having no target at all, which is where most Americans currently stand.[19]

The Power of Starting Early: How Compound Interest Accelerates Retirement Savings

No retirement planning concept is more powerful—or more frequently underestimated—than the effect of time on compound growth. Consider three investors who each contribute $500 per month into a diversified portfolio earning a 7% real (inflation-adjusted) annual return. The only difference between them is when they start. Investor A begins at age 25 and invests for 40 years until retirement at 65. Investor B starts at 35 and invests for 30 years. Investor C waits until 45 and invests for 20 years. The results are not merely different—they are staggeringly different.

Investor A, contributing $500 per month for 40 years, accumulates approximately $1.31 million on total contributions of just $240,000. Investor B, starting ten years later, accumulates approximately $610,000 on contributions of $180,000. Investor C, starting twenty years later, accumulates approximately $260,000 on contributions of $120,000. The person who started at 25 ends up with more than twice what the person who started at 35 accumulates, and more than five times what the late starter achieves—despite contributing only $60,000 and $120,000 more, respectively. That extra $700,000 and $1,050,000 is not money you saved; it is money that your money earned for you while you slept, worked, and lived your life.

What makes these numbers even more striking is what happens in the final decade. For Investor A, the portfolio grew from approximately $610,000 at year 30 to $1.31 million at year 40. That last decade alone added roughly $700,000—nearly three times what the entire first twenty years of investing produced ($260,000). This is the "last decade effect" of compound growth: the final ten years of a long investment horizon contribute more absolute dollar growth than the first twenty combined, because returns are being earned on an ever-larger base. It is the single most compelling argument for starting early: you are not just buying more years of returns, you are buying access to the exponential part of the growth curve.

These scenarios use a 7% real return, which reflects the long-term historical average of the S&P 500 (approximately 10% nominal minus roughly 3% average inflation since 1926). Your actual returns will vary year to year, and there are no guarantees. But the underlying principle is mathematical, not speculative: money that compounds for 40 years will always vastly outperform money that compounds for 20 years, regardless of the exact rate. If you want to explore what your own monthly contribution, starting age, and expected return might produce, try running the numbers in a compound interest calculator—the results often surprise even experienced investors.

Tax-Advantaged Accounts: Your Retirement Savings Toolkit

The federal government provides powerful tax incentives to encourage retirement saving, and the order in which you use these accounts can make a six-figure difference over your career. For 2026, the IRS has set 401(k) contributions at $24,500 ($32,500 for ages 50 and older, and $35,750 for ages 60-63 under the SECURE 2.0 super catch-up provision), with IRA contributions at $7,500 ($8,600 for ages 50+). For a detailed breakdown of Roth vs. Traditional IRA income thresholds, deduction phase-outs, and the backdoor Roth strategy, see our complete Roth IRA vs. Traditional IRA guide.[4, 5, 6]

Most financial planners recommend a specific priority order for deploying retirement savings. First, contribute enough to your employer's 401(k) to capture the full employer match—this is an instant 50% to 100% return on your money, depending on the match formula, and there is no investment on earth that reliably produces that. Second, if eligible, max out a Health Savings Account (HSA): the HSA offers a unique triple tax benefit—contributions are tax-deductible, growth is tax-free, and withdrawals for qualified medical expenses are tax-free, making it the most tax-efficient account in the U.S. tax code. Third, fund a Roth IRA if your income permits (the tax-free growth is especially valuable for young investors with decades of compounding ahead). Fourth, go back and max out your 401(k) to the full $24,500 limit. Only after exhausting all tax-advantaged space should you invest in a taxable brokerage account.

The SECURE 2.0 Act, which took effect in stages starting in 2023, introduced several provisions designed to boost participation. Beginning in 2025, new 401(k) and 403(b) plans must automatically enroll eligible employees at a contribution rate of at least 3%, with automatic annual escalation of 1% per year up to at least 10%. This "opt-out" design has been shown to dramatically increase participation rates—Vanguard's 2025 "How America Saves" report shows that plans with auto-enrollment achieve participation rates above 90%, compared to roughly 65% for voluntary-enrollment plans. If your employer recently adopted auto-enrollment, make sure to check that your contribution rate and investment selection align with your retirement goals rather than just accepting the default.[6, 20]

One often-overlooked detail: the SECURE 2.0 mandatory Roth catch-up rule that takes effect in 2026 requires employees who earned over $150,000 in FICA wages in the prior year to make all 401(k) catch-up contributions on a Roth (after-tax) basis. If you are a high earner over 50, this means your catch-up dollars will grow tax-free—a significant long-term benefit, even though it increases your current tax bill. Understanding these account mechanics is essential for maximizing the government's retirement incentives, but the most important step is also the simplest: contribute something, as early and as consistently as possible.[23]

Savings Rate vs. Investment Returns: Which Matters More for Retirement?

New investors often obsess over finding the perfect investment—the fund with the best track record, the sector with the most momentum. But decades of research and data from Vanguard and Fidelity point to a counterintuitive truth: in the first decade of accumulation, your savings rate matters far more than your investment return. On a $10,000 portfolio, the difference between earning 6% and 8% is just $200 per year. But increasing your monthly contribution by $200 adds $2,400 per year to your portfolio—twelve times the impact of chasing better returns.[20, 19]

This dynamic flips as your portfolio grows. After 15 to 20 years of consistent saving, the portfolio itself becomes large enough that market returns generate more absolute dollar growth than your contributions. Consider someone with a $500,000 portfolio still contributing $500 per month ($6,000 per year). At a 7% return, the portfolio generates $35,000 in growth that year—nearly six times the annual contribution. At this stage, investment selection, asset allocation, and fee minimization become the dominant drivers of wealth accumulation. The crossover point—where returns overtake contributions—typically occurs somewhere between year 12 and year 18, depending on your savings rate and market performance.

Fidelity recommends a 15% total savings rate—including any employer match—as the target for a comfortable retirement. If you are currently saving 6% with a 3% employer match (total 9%), closing the gap to 15% might feel daunting. But you do not have to get there overnight. Increase your contribution rate by 1 percentage point each year, timed to coincide with your annual raise so you never feel the reduction in take-home pay. Going from 9% to 10% this year, 11% next year, and so on means you reach 15% in just six years—and your portfolio barely notices the transition because your salary is rising at the same time.[17]

The practical takeaway is straightforward: in your 20s and 30s, focus relentlessly on savings rate. Automate your contributions, capture your full employer match, and increase your rate by 1% per year. In your 40s and 50s, keep your savings rate high but begin paying closer attention to investment costs, asset allocation, and tax efficiency—because by then, these factors are working on a much larger base and their compounding effect becomes the primary engine of growth.

Catch-Up Strategies for Late Starters: It Is Not Too Late

If you are in your 40s or 50s with little saved for retirement, the compound growth scenarios above might feel more discouraging than inspiring. But the math also works in your favor in specific ways. A 45-year-old earning $90,000 who aggressively saves 25% of income ($22,500/year or $1,875/month) at a 7% real return for 20 years accumulates approximately $975,000—close to the Fidelity 10× benchmark for that salary. Add an employer 401(k) match of 4% ($3,600/year), and the total climbs above $1.1 million. The catch-up is demanding but achievable, especially if combined with the strategies below.

The first strategy is to fully utilize every tax-advantaged account available to you. Once you turn 50, the IRS allows additional catch-up contributions: $8,000 extra on your 401(k) (or $11,250 if you are 60-63 under SECURE 2.0's super catch-up) and $1,100 extra on your IRA. A 60-year-old can shelter up to $35,750 in a 401(k), $8,600 in an IRA, and $4,400 in an HSA (individual coverage)—a combined $48,750 per year in tax-advantaged space. The second strategy attacks the other side of the equation: reduce your projected retirement spending. Every $1,000 you cut from annual expenses reduces your required portfolio by $25,000 under the Rule of 25. Downsizing your home, eliminating a car payment, or moving to a lower-cost area creates a dual benefit—more money to save today and a smaller target to hit.[25]

The third strategy is to plan for partial income in early retirement. Working part-time, consulting, or freelancing for even a few years after leaving full-time employment can dramatically reduce the portfolio drawdown in those critical early years (remember sequence-of-returns risk from Section 2). Earning just $20,000 per year in bridge income means you withdraw $20,000 less from your portfolio annually, which in turn means your portfolio needs to be $500,000 smaller at retirement (under the Rule of 25). The fourth strategy, available to anyone, is to delay claiming Social Security benefits. For every year you delay beyond your full retirement age (currently 67 for those born in 1960 or later), your benefit increases by approximately 8% per year, up to age 70. That is a guaranteed, inflation-adjusted 8% annual return—an extraordinary deal that no market investment can match.[15, 14]

If you are starting late and wondering how to deploy a lump sum (such as an inheritance or home equity) versus spreading contributions over time, our dollar-cost averaging vs. lump sum guide walks through the research on both approaches. The key message for late starters is this: the "best" time to start saving was in your 20s, but the second-best time is right now. The combination of aggressive savings, catch-up contributions, expense reduction, bridge income, and delayed Social Security can close a surprisingly large gap—especially when compound growth still has 15 to 25 years to work its math.

How Inflation, Taxes, and Fees Erode Your Retirement Savings

The 10% nominal annual return that the S&P 500 has averaged since 1926 is a headline number that overstates what you actually get to keep. Three forces work relentlessly to shrink your real, after-tax wealth: inflation, taxes, and investment fees. As of January 2026, the Bureau of Labor Statistics reports CPI inflation at 2.4% year-over-year—moderate by historical standards but still enough to cut the purchasing power of $100,000 to roughly $62,000 over 20 years if left unprotected. For a deeper exploration of how inflation transforms your nominal returns into real purchasing power, and the precise mathematics of the Fisher equation, see our complete guide to real rate of return.[13]

Taxes take a second bite. Under the 2026 federal tax brackets (which reflect the TCJA rates made permanent by the One Big Beautiful Bill Act), long-term capital gains are taxed at 0%, 15%, or 20% depending on income—plus a potential 3.8% Net Investment Income Tax (NIIT) for high earners. In a taxable account, these taxes can reduce your effective annual return by 1.0% to 2.0% or more, depending on turnover and dividend frequency. Tax-advantaged accounts (401(k), IRA, Roth) defer or eliminate this drag, which is precisely why maximizing them is so critical. For strategies to offset taxable gains, including harvesting losses to reduce your tax bill, see our tax-loss harvesting guide.[24, 7]

Investment fees are the third and often most insidious drag, because they compound against you silently. The difference between a fund charging 0.03% (typical of a broad index ETF) and one charging 0.50% (common for actively managed funds) may seem trivial in any single year. But FINRA's investor education resources illustrate the cumulative impact: on a $100,000 portfolio earning 8% annually, the 0.47% fee difference results in approximately $130,000 less wealth over 30 years—money that went to the fund company instead of your retirement. For a deep dive into the data on index funds versus actively managed funds and how fee structures compound over decades, see our index funds vs. active funds analysis.[11]

When all three forces act simultaneously, the impact is dramatic. A rough but illustrative calculation: 10% nominal return minus 2.5% inflation minus 1.5% tax drag minus 0.5% in fees leaves an effective real after-tax return of approximately 5.5%. That is still positive and still compounds powerfully over decades—but it is barely half the headline 10% number. This is why every retirement projection in this guide uses a 7% real return (which already accounts for inflation) rather than the feel-good 10% nominal figure. Planning with realistic assumptions is the single best way to avoid a retirement shortfall.

Building Your Retirement Portfolio: From Accumulation to Distribution

Your retirement portfolio should evolve as you move through three distinct phases: accumulation, transition, and distribution. In the accumulation phase—roughly your 20s through mid-40s—the goal is maximum long-term growth. With 20 to 40 years until retirement, you can afford to hold 80% to 90% of your portfolio in equities (broadly diversified stock index funds) and 10% to 20% in bonds. Short-term volatility is irrelevant at this stage because you have decades to recover from any market decline. The J.P. Morgan Guide to Retirement shows that even the worst 20-year period in S&P 500 history still produced positive real returns, reinforcing the case for aggressive equity allocation during accumulation.[21]

In the transition phase—your late 40s through early 60s—you gradually shift toward a more balanced allocation. The classic "glide path" used by target-date funds reduces equity exposure by roughly 1 to 2 percentage points per year, landing at approximately 50/50 stocks and bonds by retirement age. Schwab's retirement planning framework suggests that someone five to ten years from retirement should hold 40% to 60% in equities, with the remainder in investment-grade bonds, Treasury securities, and short-term reserves. The goal is to protect the gains you have accumulated while still maintaining enough growth potential to outpace inflation. Moving to 100% bonds too early sacrifices the equity premium that could add hundreds of thousands of dollars over the final decade before retirement.[22]

Once you enter the distribution phase—retirement itself—the portfolio's job changes from growing as fast as possible to providing reliable income while preserving purchasing power. One popular approach is the "bucket strategy." Bucket one holds one to two years of living expenses in cash or money market funds, providing a buffer so you never have to sell stocks in a down market. Bucket two holds three to seven years of expenses in short-to-intermediate-term bonds, which generate modest income and can be tapped when equities are declining. Bucket three holds the remainder in diversified equities, which continue to grow over time and periodically refill the bond and cash buckets during strong market years. For a comprehensive discussion of how to construct each bucket and how different asset classes interact, see our asset allocation and diversification guide.

If the idea of managing a three-bucket system feels overwhelming, target-date funds offer a fully automated alternative. Companies like Vanguard and Fidelity offer "through retirement" target-date funds that continue adjusting your allocation well into your retirement years. These funds automatically execute the glide path, rebalance across asset classes, and handle the complexity for a typical expense ratio of 0.10% to 0.15%—far less than the cost of most financial advisors. For investors who want dividend income as a component of their retirement cash flow, our dividend reinvestment guide explains when to DRIP and when to take dividends as cash.

Frequently Asked Questions About Retirement Savings

Below are answers to the most common questions about retirement savings planning, grounded in data from the SEC, IRS, and leading research firms.[9, 8]

Key Takeaways: Your Retirement Savings Action Plan

Building a retirement savings plan does not require a financial advisor, a complex spreadsheet, or a finance degree. It requires understanding a few core principles and then acting on them consistently. Here is your action plan, distilled from the data and research presented throughout this guide:

Calculate your retirement number. Estimate your annual retirement spending, subtract expected Social Security income, and multiply the remainder by 25. This is the portfolio value you are building toward. Know your milestone. Compare your current retirement savings to the Fidelity salary multiples for your age (1× by 30, 3× by 40, 6× by 50, 8× by 60, 10× by 67) to see whether you are on track, ahead, or behind. Save at least 15% of income including your employer match, and increase your rate by 1 percentage point each year until you reach your target. Prioritize tax-advantaged accounts in the correct order: employer match first, then HSA, then Roth IRA, then max out your 401(k), then taxable brokerage.

Use real returns for all projections—7% for equities, not the 10% nominal headline. Keep investment fees below 0.20% by using low-cost index funds. Start now, regardless of your age or current savings level. Time in the market is the single most powerful variable in the compound growth equation, and every month of delay costs more than the last. The difference between starting at 25 and 35 with $500 per month is over $700,000 by retirement. The difference between starting today and starting next year is real money that can never be recovered.