Last updated: May 2026
Project your 401k balance, monthly income in retirement, and how long your savings will last.
Your Details
Savings & Contributions
Return & Inflation Assumptions
Growth Breakdown
Milestone Projection
Compound growth: Balance grows monthly at (annual return ÷ 12). Monthly contribution + employer match added each month.
Employer match: Calculated as (your monthly contribution × match %) up to the match cap limit.
Monthly income (4% rule): Final balance × withdrawal rate ÷ 12. The 4% rule is a guideline suggesting you can withdraw 4% annually with low risk of running out over 30 years.
Years of runway: Estimated years your balance sustains withdrawals, assuming 4% annual return in retirement and inflation-adjusted spending.
⚠️ Projections assume constant returns and contributions. Actual results depend on market performance, tax treatment, and life changes. Consult a financial advisor for personalized retirement planning.
This calculator projects your retirement savings using compound growth and estimates how long your money will last using the 4% rule — the most widely cited sustainable withdrawal guideline in financial planning.
The 4% rule comes from the Trinity Study (1994, updated 2009), which found that a portfolio of 50-75% stocks withdrawing 4% annually adjusted for inflation had a 95%+ success rate over 30-year retirement periods historically. At 4% withdrawal, your savings need to be approximately 25x your annual expenses at retirement.
Worked example: $80,000/year in current expenses at retirement. Target nest egg: $80,000 x 25 = $2,000,000. Starting at age 35 with $50,000 saved, contributing $1,500/month at 7% annual return: you reach $2M at approximately age 62 — 27 years of growth.
The 4% rule remains a widely used starting point, but some financial planners now recommend 3-3.5% given longer retirements and periods of lower expected returns. The rule was based on 30-year retirements; if you retire at 55 and live to 90, a 35-year horizon makes 3.5% more conservative. The Morningstar Center for Retirement Research (2022) suggested 3.3% as a more current safe withdrawal rate for new retirees.
The 25x rule (divide your annual expenses by 4%) gives a quick estimate. For $60,000/year in retirement spending: $60,000 x 25 = $1,500,000. For $100,000/year: $2,500,000. This does not include Social Security income, which reduces how much you need to withdraw from savings. The SSA estimates average Social Security retirement benefits at approximately $1,900/month ($22,800/year) in 2026.
For a diversified stock/bond portfolio, most financial planners use 6-7% nominal return (before inflation) for projections. The S&P 500 has averaged roughly 10% annually since 1926, but a portfolio with bonds will return less. For real (inflation-adjusted) projections, subtract 2.5-3% for inflation, giving a 4-5% real return assumption for a balanced portfolio.
Yes — Social Security meaningfully reduces the portfolio size you need. You can estimate your Social Security benefit at SSA.gov using your earnings history. A person earning $75,000/year who claims at 67 (full retirement age) can expect roughly $2,200-$2,500/month. Delaying to age 70 increases benefits by 8% per year, potentially adding $400-$600/month.
Maximizing tax-advantaged retirement accounts is the single most powerful step most workers can take toward a secure retirement. Contributions to traditional accounts reduce your taxable income today; Roth contributions grow tax-free forever. Understanding the limits — and taking full advantage of employer matches — is essential before putting money in taxable accounts.
The IRS adjusts contribution limits most years for inflation. The table below reflects 2025 limits. The catch-up contributions for workers 50 and older are especially valuable: a 55-year-old maxing out a 401(k) with catch-up adds $31,000/year in tax-advantaged savings.
| Account Type | Employee Limit | Catch-Up (50+) | Employer Match | Tax Treatment |
|---|---|---|---|---|
| 401(k) | $23,500 | +$7,500 | Up to 100% match | Pre-tax or Roth |
| 403(b) | $23,500 | +$7,500 | Varies | Pre-tax or Roth |
| IRA Traditional | $7,000 | +$1,000 | N/A | Pre-tax if eligible |
| Roth IRA | $7,000 | +$1,000 | N/A | After-tax / tax-free growth |
| SEP-IRA | 25% of comp up to $70,000 | N/A | Employer only | Pre-tax |
| SIMPLE IRA | $16,500 | +$3,500 | Up to 3% match | Pre-tax |
How much do I need to retire?
The 25x rule is the most widely used shortcut: multiply your expected annual retirement spending by 25. For $60,000/year that is $1,500,000. For $80,000/year it is $2,000,000. This assumes the 4% withdrawal rate and a 30-year retirement. Factor in Social Security income to reduce the portfolio target accordingly.
What is the 4% rule?
The 4% rule originates from the 1994 Trinity Study. Researchers found that a diversified stock/bond portfolio could sustain annual withdrawals of 4% of the initial balance (adjusted for inflation each year) with a 95%+ success rate over 30 years of historical market data. It is a guideline, not a guarantee — longer retirements or periods of poor early returns can challenge it.
Should I choose traditional or Roth 401(k)?
If you expect to be in a higher tax bracket in retirement than today, Roth contributions are usually better — you pay tax now at a lower rate. If you expect a lower bracket in retirement (common for high earners nearing peak salary), traditional pre-tax contributions save more today. Many planners recommend splitting contributions between both to hedge against future tax changes.
When can I withdraw from retirement accounts?
For 401(k)s and traditional IRAs, penalty-free withdrawals begin at age 59½. Early withdrawals typically incur a 10% penalty plus income tax. Roth IRA contributions (not earnings) can be withdrawn at any age without penalty. Required Minimum Distributions (RMDs) from traditional accounts start at age 73 under current law.
How does compound growth affect retirement savings?
Compound growth is the primary engine of retirement wealth. A dollar invested at 30 has 35 years to compound before a typical retirement at 65 — at 7% it grows to roughly $11. A dollar invested at 45 only has 20 years and grows to about $3.87. This is why starting early — even with small amounts — matters far more than contributing large amounts later.