Retirement Planning · 2026

Retirement Planning Calculator

Find the three numbers that define your retirement: the nest egg you’ll need, how much to invest every month to build it, and how long your money must last — all adjusted for inflation and Social Security, using realistic US assumptions.

Updated Jul 18, 2026 Reviewed by the BSF CPA Editorial Team Based on the 4% rule & 2026 limits 10 min read
Quick Answer

A 35-year-old spending $5,000/month who retires at 65 needs a nest egg of roughly $1.7 million — after ~$2,000/month of Social Security and 3% inflation. Starting from $50,000 already saved, that’s about $1,100 per month invested. Start at 25 instead of 35 and the same goal takes only about $380/month — the clearest illustration of why time in the market beats timing it.

Retirement Planning Calculator

Your plan

Educational estimate. Assumes constant returns and steady contributions, which real markets never deliver. Excludes taxes on withdrawals, pensions, and sequence-of-returns risk. Not financial advice.

Your retirement plan

30 yrs to go
Nest egg needed at retirement
$1,717,712
Invest per month
$1,096
Expenses at retirement
$12,136
Social Security covers
$4,855
Current savings grow to
$380,613
Years in retirement
25

Figures are in future (nominal) dollars at your retirement date. The nest egg funds inflation-adjusted withdrawals for your full life expectancy, net of Social Security.

What your result means

The nest egg looks enormous because it’s in future dollars and must fund decades of inflation-adjusted spending — but Social Security and three decades of compounding do most of the heavy lifting. Your monthly contribution is the one number fully within your control.

What this calculator does

Most retirement calculators answer only one question. This one answers all three that actually matter: how much you’ll need at retirement (your nest egg), how much to invest each month to build it, and how long it has to last. It inflates today’s spending to your retirement date, subtracts the Social Security you expect, and sizes the portfolio needed to fund the rest for your full life expectancy.

Who should use it

Anyone with a paycheck and a plan to eventually stop earning one — whether you’re 25 and starting, 45 and catching up, or 60 and checking your landing. It’s equally useful for advisors sanity-checking a client’s trajectory and for FIRE-minded savers stress-testing an early exit.

When to use it

Re-run it after any life change — a raise, a move, a new child, a market swing — and at least once a year. Retirement planning isn’t a one-time calculation; it’s a number you steer toward and adjust as reality unfolds.

Scope & limits

This is a planning model, not a guarantee. It assumes steady returns and contributions, ignores taxes on withdrawals (traditional 401(k)/IRA money is taxed as income; Roth is not), and doesn’t model sequence-of-returns risk — the danger of a crash early in retirement. Treat the output as a target to plan around, then build in a margin of safety.

How retirement math works

Two forces make the numbers look intimidating. First, inflation: at 3% a year, $5,000 of monthly spending today becomes about $12,100 in 30 years — the same lifestyle, more than double the dollars. Second, longevity: a modern retirement can last 25–30 years, so your portfolio has to fund 300+ months of inflation-adjusted withdrawals.

The good news is that compounding works just as hard for you on the way up. A steady monthly contribution invested for decades does the vast majority of the work — your own contributions are often less than a third of the final balance. And Social Security meaningfully reduces the private savings you need to shoulder yourself.

The formula (three steps)

Step 1 — inflate today’s spending to your retirement date: Future expenses = Current expenses × (1 + inflation)years to retirement Step 2 — size the nest egg to fund inflation-adjusted withdrawals (net of Social Security): Nest egg = (Future annual expenses − Social Security) × [1 − (1 + r)−N] ÷ r where r = real return = (1 + post-retirement return) ÷ (1 + inflation) − 1, N = years in retirement Step 3 — the monthly contribution to close the gap: Monthly invest = (Nest egg − future value of current savings) × i ÷ [(1 + i)n − 1] where i = monthly pre-retirement return, n = months to retirement

Using the real return in Step 2 is what keeps withdrawals rising with inflation throughout retirement — a subtlety many simpler calculators skip, which is why they understate the target.

The 4% rule and the 25× target

A famous shortcut: you can withdraw about 4% of your portfolio in the first year of retirement, then adjust that dollar amount for inflation each year, with a high probability the money lasts 30 years. Flip it around and you get the 25× rule — you need roughly 25 times your annual expenses saved (because 1 ÷ 0.04 = 25).

This calculator is more precise than the 25× shortcut because it accounts for your actual time horizon, your return assumptions, and Social Security — but the 4% rule is a useful gut-check. If you need $80,000 a year from your portfolio, 25× says roughly $2 million; use this tool to refine that with your real numbers. FIRE savers often use a stricter 3–3.5% rate to fund a longer retirement.

Worked examples

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Example 1 — Mid-career professional ($5,000/mo, age 35)

Retire at 65, live to 90, $50k saved, $2,000/mo Social Security, 3% inflation.

Expenses inflate to about $12,100/month by 65. Social Security (grown with COLA) covers roughly $4,900, leaving a portfolio to fund ~$7,300/month for 25 years — a nest egg near $1.7 million. With $50,000 already invested and 30 years of 7% growth, the required contribution is about $1,100/month. Entirely achievable with a maxed-out 401(k) match and steady discipline.

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Example 2 — Late starter ($6,000/mo, age 50)

Retire at 65, live to 90, $100k saved, $2,500/mo Social Security.

With only 15 years to compound, the required contribution jumps to roughly $3,200/month for a ~$1.3M nest egg — far more than the 35-year-old, for a smaller goal. This is the cost of a late start, and it’s exactly why catch-up contributions (an extra $8,000 in a 401(k) at 50+) exist. Working two extra years to 67 would cut this substantially.

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Example 3 — Early starter ($4,000/mo, age 25)

Retire at 65, live to 90, $10k saved, $2,000/mo Social Security, 8% return.

Forty years of compounding is transformative: the required contribution is only about $380/month to reach a ~$1.5M nest egg. The 25-year-old invests a fraction of what the 50-year-old does and still lands softer. Starting early is the single most powerful move in this entire calculation.

How to interpret your results

The nest egg is a future, nominal number — don’t be alarmed by the size. In today’s purchasing power it’s far smaller, and it’s designed to be drawn down to near zero over your lifetime, not preserved forever. The number to focus on is the monthly contribution: it’s concrete, it’s under your control, and it’s the lever you adjust as your income grows.

A reality check on returns

Assumptions drive everything. An 11–12% pre-retirement return is optimistic; 7–8% before inflation is more defensible for a diversified portfolio, and 4–5% is prudent once you’re retired and more conservatively invested. It’s far better to plan with cautious numbers and be pleasantly surprised than to assume heroic returns and fall short.

Don’t forget taxes

A traditional 401(k) or IRA is taxed as ordinary income when you withdraw it, so a $1.7M balance isn’t $1.7M of spending power. Roth accounts come out tax-free. A realistic plan blends both — and this is where a conversation with a CPA or fee-only advisor pays for itself.

The levers you can pull

  • Start earlier. The most powerful lever by far. Beginning at 25 instead of 35 can roughly halve the required monthly contribution.
  • Delay retirement by 2–3 years. A triple win: more years contributing, more years compounding, and fewer years to fund — plus a larger Social Security benefit.
  • Spend less in retirement. Every $500/month you don’t need cuts the required nest egg by roughly $100,000–$150,000.
  • Step up contributions with raises. Increasing what you invest by even 3–5% a year, in line with pay, dramatically improves the outcome without feeling like a sacrifice.
  • Maximize the match and tax-advantaged space. An employer 401(k) match is an immediate, guaranteed return you should never leave on the table.

Retirement savings benchmarks by age

A widely used rule of thumb (Fidelity) for how many times your annual salary to have saved, as a rough trajectory check:

AgeTarget saved (× salary)Roughly on $80k salary
301×$80,000
403×$240,000
506×$480,000
608×$640,000
6710×$800,000

These are guideposts, not gospel — your own number depends on your spending, Social Security, and retirement age. Use the calculator above for a target tailored to you.

Common mistakes

  • Ignoring inflation. Planning in today’s dollars badly understates what you’ll need decades out. This tool inflates for you.
  • Assuming unrealistic returns. Double-digit forever is a fantasy. Use 7–8% pre-retirement, 4–5% after.
  • Forgetting taxes on withdrawals. Traditional accounts are taxed as income; budget for it or lean on Roth.
  • Overcounting Social Security. It replaces roughly 30–40% of pre-retirement income for average earners — helpful, not sufficient. Verify your estimate at ssa.gov.
  • Starting late and hoping. The math is unforgiving about lost decades. If you’re behind, use catch-up contributions and consider working a little longer.
  • Ignoring sequence-of-returns risk. A crash in your first retirement years hurts far more than the same crash later. Keep a cash buffer to avoid selling into a downturn.

Best practices & 2026 contribution limits

A planner’s checklist

Capture the full employer 401(k) match first — it’s free money · Max tax-advantaged space in 2026: 401(k) $24,500 (plus $8,000 catch-up at 50+, or $11,250 at ages 60–63), IRA $7,500 ($1,100 catch-up), HSA $4,400 self / $8,750 family · Automate contributions and step them up with every raise · Keep a Roth/traditional mix for tax flexibility in retirement · Hold 1–2 years of expenses in cash near retirement to weather downturns · Re-run this plan yearly and after any big life change · Verify your Social Security estimate at ssa.gov.

Frequently asked questions

How much do I need to retire?
A common rule is 25× your annual expenses (the 4% rule), so $60,000/year of spending implies about $1.5 million in today’s dollars. This calculator refines that with your age, time horizon, inflation, expected returns, and Social Security to give a target tailored to you — usually a larger nominal number because it’s in future dollars.
What is the 4% rule?
It suggests you can withdraw 4% of your portfolio in your first retirement year, then adjust that dollar amount for inflation each year, with a strong chance the money lasts 30 years. It’s a useful benchmark; early retirees often use a more conservative 3–3.5% because their retirement is longer.
How much should I have saved by my age?
A rough Fidelity guideline: 1× your salary by 30, 3× by 40, 6× by 50, 8× by 60, and 10× by 67. These are trajectory checks, not precise targets — your real number depends on spending and retirement age.
What return should I assume?
Before retirement, 7–8% per year before inflation is defensible for a diversified stock-heavy portfolio. In retirement, use a more conservative 4–5% as you shift toward bonds. Assuming 10%+ is optimistic and risks under-saving.
Should I include Social Security?
Yes, but conservatively. For average earners it replaces roughly 30–40% of pre-retirement income. Enter your estimated benefit (check ssa.gov) and the calculator subtracts it from the income your portfolio must provide. Enter 0 if you’d rather plan without it as a safety margin.
What are the 2026 contribution limits?
401(k): $24,500, plus an $8,000 catch-up at 50+ (or $11,250 at ages 60–63). IRA: $7,500, plus $1,100 catch-up. HSA: $4,400 self-only / $8,750 family, plus $1,000 catch-up at 55+. Maxing these is the fastest route to your target.
How does inflation affect my plan?
Significantly. At 3% inflation, prices roughly double every 24 years, so the dollars you’ll need in retirement are far larger than today’s. This calculator inflates your expenses to your retirement date and keeps withdrawals rising with inflation throughout retirement.
Will I owe taxes on my retirement savings?
On traditional 401(k) and IRA money, yes — withdrawals are taxed as ordinary income. Roth withdrawals are tax-free. Because of this, a $1.5M traditional balance provides less spendable income than the same Roth balance. A blend of both gives you flexibility.
What is sequence-of-returns risk?
The danger that a market downturn early in retirement, while you’re withdrawing, permanently damages your portfolio. The same average return with a bad start can run out decades sooner. Holding a cash buffer and staying flexible on spending are the main defenses.
Can I retire early with this?
Yes — set your retirement age lower and your life expectancy the same, and you’ll see the nest egg rise sharply because you fund more years from fewer. FIRE planners typically also use a stricter 3–3.5% withdrawal rate. Our FIRE calculator is purpose-built for this.
How often should I update my plan?
At least annually, and after any major change — a raise, a move, a new child, a market swing, or a shift in your target retirement date. Retirement planning is a number you steer toward, not set once.
Is this financial advice?
No. It’s an educational estimate using simplified assumptions. For a plan tailored to your taxes, accounts, and goals, consult a CPA or a fee-only fiduciary financial advisor.

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