Answer: Enter your values and the Retirement Calculator returns the exact result instantly — formula, worked example, and a plain-English explanation are included below the tool.
A retirement calculator projects whether your current savings rate and expected returns will fund your target retirement income, and what age your money will run out or last until.
Will you have enough to retire?
This retirement calculator projects how a savings balance grows to retirement age using compound growth and regular contributions, then estimates how long the portfolio lasts under withdrawals. All scenarios run locally in your browser.
Retirement math is compound interest plus withdrawals — two formulas that interact over decades. Seeing the mechanics makes the trade-offs (save more, retire later, spend less) concrete.
Balances compound: each year's growth applies to the balance plus new contributions. The future value of a lump sum is P × (1 + r)^n; a recurring annual contribution C grows to C × ((1 + r)^n − 1) ÷ r. At 7% average real-ish nominal growth, money doubles about every 10.3 years (72 ÷ 7, the Rule of 72).
Sequence: start balance, add contributions, apply growth on the average (or year-end) balance, repeat. The tool iterates year by year so you can see the curve bend upward as growth on growth dominates new deposits.
The table shows computed growth of a 10,000 dollar lump sum at several rates and horizons, exactly per (1 + r)^n. Ten thousand dollars at 7% for 20 years is 10,000 × 1.07^20 = 38,697.
Inflation is the silent counterparty: at 3% average inflation, prices double roughly every 24 years (72 ÷ 3), so a 7% nominal return is about a 4% real return. Long-range planning should use real (inflation-adjusted) figures so 'a million dollars' means the same thing in both decades.
| Lump sum | 10 years | 20 years | 40 years |
|---|---|---|---|
| $10,000 @ 4% | $14,802 | $21,911 | $48,010 |
| $10,000 @ 6% | $17,908 | $32,071 | $102,857 |
| $10,000 @ 7% | $19,672 | $38,697 | $149,745 |
| $10,000 @ 8% | $21,589 | $46,610 | $218,106 |
The well-known 4% rule comes from the 1994 Bengen study and the Trinity University analyses: a portfolio split between stocks and bonds historically sustained inflation-adjusted withdrawals starting at 4% of the initial balance over 30-year retirements in most historical periods. It's a planning guideline, not a guarantee — later research suggests flexibility (3.5 to 4%) improves resilience after expensive markets.
Inverting it: every 1 dollar of annual spending needs roughly 25 dollars saved (1 ÷ 0.04). A 40,000-dollar-a-year lifestyle implies a 1,000,000-dollar portfolio, before Social Security or pensions reduce the gap.
Social Security replaces a meaningful share of pre-retirement income — around 40% of the average worker's earnings, per the Social Security Administration — but benefits claim earlier than full retirement age are permanently reduced, while delaying past full retirement age credits benefits up to age 70 (8% per year for those with a full retirement age of 67).
A practical plan layers income: guaranteed floors first (Social Security, pensions, annuities covering essentials), then portfolio withdrawals for flexible spending. Withdrawal order matters for taxes — generally taxable accounts first, then tax-deferred, then Roth — though the optimal sequence varies by bracket.
['Tax treatment defines account types: traditional (pre-tax) contributions reduce taxable income now and are taxed on withdrawal; Roth contributions are taxed now and grow tax-free. Employer plans (401(k)/403(b)) have much higher limits than IRAs — for 2025, 23,500 dollars for 401(k)s versus 7,000 dollars for IRAs, with an extra 7,500-dollar catch-up at age 50 plus a new higher catch-up at 60 to 63 under SECURE 2.0.', 'The match is the first priority: a typical match of 50% up to 6% of pay is an immediate 50% (or up to 3% of salary) return no market can match. Second priority is filling high-interest debt payoff, then maximizing tax-advantaged space, then taxable investing.', 'Asset location complements asset allocation: hold the highest-growth assets where compounding escapes tax drag (Roth), tax-inefficient assets (bonds, REITs) in tax-deferred accounts, and tax-efficient index funds in taxable accounts. The ordering subtleties matter more as balances grow past six figures.']
How much do I need to retire?
A common guideline is 25× your expected annual spending — from the 4% safe-withdrawal research — minus guaranteed income like Social Security. Spending 40,000 dollars a year beyond Social Security implies roughly 1,000,000 dollars in savings.
What is the 4 percent rule?
Drawing 4% of your starting portfolio balance in year one, then adjusting that dollar amount for inflation each year, historically lasted 30 years across most US market periods (Bengen 1994; Trinity study). Treat it as a planning heuristic, not a guarantee — flexible spending improves outcomes.
How does compound growth actually work?
Growth earns growth: 10,000 dollars at 7% becomes 10,700, then 11,449 — the second year's gain includes gains on gains. After 20 years at 7%, 10,000 dollars reaches 38,697. More time matters more than a higher rate.
When should I claim Social Security?
Claiming before full retirement age permanently reduces monthly benefits; delaying to age 70 increases them by 8% per year for those with a full retirement age of 67. The break-even age is typically around 80 to 82, so longevity expectations and health coverage should drive the choice.
How does inflation affect my retirement plan?
At 3% average inflation, purchasing power halves in about 24 years (72 ÷ 3), spanning a long retirement. Plan in real dollars: subtract inflation from expected returns, or your far-future numbers will quietly buy less than today's.