Retirement Calculator
Project your retirement corpus and required monthly contributions.
About the Retirement Calculator
This retirement calculator projects the size of your retirement corpus by combining the future value of your current savings with the future value of ongoing monthly contributions. Enter your current retirement account balance, your planned monthly contribution, an assumed annual return rate, and the number of years until retirement, and the tool returns the projected corpus at retirement plus a breakdown showing how much comes from your contributions versus investment growth.
The breakdown is often eye-opening. Over a 30-40 year horizon, investment growth typically contributes 60-75% of the final corpus — far more than the raw contributions. This is why starting early matters so much: a worker who saves $500/month from age 25 to 65 ends up with about $1.2 million at 7%, while a worker who starts at 35 and saves the same amount ends up with about $565,000 — less than half, despite contributing only 25% less out of pocket.
The calculator works for any retirement vehicle: 401(k), IRA, Roth IRA, SEP-IRA, pension, or taxable brokerage account. It does not separately model tax treatment, employer match, or Social Security — see the limitations and FAQ for guidance.
How It Works
The calculator combines two future-value formulas. First, the future value of your current savings (a lump sum):
FV_lump = PV * (1 + r)^nSecond, the future value of monthly contributions (an annuity, where contributions are made monthly but compounded annually):
FV_annuity = PMT * 12 * ((1 + r)^n - 1) / rWhere PV is current savings, PMT is monthly contribution, r is the annual return rate (decimal), and n is years. The total corpus is FV_lump + FV_annuity. The total contributed is PV + PMT * 12 * n, and the investment growth is the difference.
The formula assumes contributions are made monthly throughout each year but compounded annually — a common simplification for retirement projections. For exact monthly compounding, the result is slightly higher (by about 4% over 30 years at 7%). For most planning purposes, the annual-compounding approximation is more than adequate.
Worked Examples
Suppose you are 35 years old with $25,000 already saved, contributing $500/month, expecting 7% annual return, retiring at 65 (30 years).
- FV of current savings: $25,000 * (1.07)^30 = $25,000 * 7.6123 = $190,307
- Annual contribution: $500 * 12 = $6,000/year
- FV of contributions: $6,000 * ((1.07)^30 - 1) / 0.07 = $6,000 * 94.461 = $566,766
- Total corpus: $190,307 + $566,766 = $757,073
- Total contributed: $25,000 + $6,000 * 30 = $205,000
- Investment growth: $757,073 - $205,000 = $552,073 (73% of corpus)
Start the same plan at age 25 instead of 35 (40 years): corpus grows to about $1.55 million — more than double, despite only 33% more contributions ($245,000 vs $205,000). The extra 10 years of compounding produces $800,000 of additional growth.
When to Use This Tool
Use this retirement calculator when:
- Projecting your 401(k) or IRA balance at age 60, 65, or 70
- Estimating the impact of starting to save 5, 10, or 15 years earlier
- Comparing a Roth IRA vs traditional IRA contribution strategy
- Deciding whether to increase your 401(k) contribution rate
- Evaluating whether you can afford to retire early (FIRE movement)
- Modeling the impact of a career break (lower contributions for a few years)
- Estimating whether you need to work an extra 5 years to reach a target corpus
The widely cited '4% rule' suggests you can withdraw 4% of your retirement corpus per year (adjusted for inflation) with high confidence of not running out over 30 years. To target a specific retirement income, divide your desired annual income by 4% (e.g., $60,000/year requires a $1.5M corpus).
Limitations & Disclaimer
This calculator assumes constant monthly contributions, a fixed annual return rate, and annual compounding of monthly contributions. It does not model inflation (use the Inflation Calculator separately), taxes on withdrawals (traditional 401k/IRA are taxed as ordinary income; Roth is tax-free), employer match, contribution limits ($23,000 for 401(k) and $7,000 for IRA in 2024), Social Security, pension income, sequence-of-returns risk, or healthcare costs in retirement. Real investment returns are volatile and not guaranteed — do not extrapolate a fixed 7% return to actual equity performance. This is an educational planning tool, not investment advice. Consult a fiduciary financial advisor for personalized retirement planning. See our disclaimer for full terms.
Frequently Asked Questions
What return rate should I use for retirement projections?
For a diversified stock-bond portfolio, 6-7% is a reasonable long-term real (inflation-adjusted) expectation based on historical U.S. returns. Use 5% for a conservative projection, 7% for a balanced portfolio, 8% for an all-equity portfolio held 30+ years. Remember that past returns don't guarantee future results.
Does this account for inflation?
No — the result is in nominal (future) dollars, which will have less purchasing power than today's dollars. For a real (inflation-adjusted) projection, either reduce the assumed return rate by expected inflation (~3%), or convert the final corpus to today's dollars using our <a href='/tools/inflation-calculator.php'>Inflation Calculator</a>.
How much should I be saving for retirement?
Financial planners commonly recommend saving 15% of gross income (including any employer match) starting in your 20s. If you start later, the percentage needs to be higher: 25% if starting at 35, 35% if starting at 45. Use this calculator to model different contribution levels and see the impact on your projected corpus.
Does this include Social Security or pension income?
No. Social Security typically provides $15,000-$40,000/year for U.S. retirees, depending on lifetime earnings. Add this separately to your retirement income projection. If you have a defined-benefit pension, add its projected annual payout to your retirement income as well.
What about employer 401(k) match?
Employer match (commonly 3-6% of salary) effectively adds to your contribution. If your employer matches $200/month on top of your $500 contribution, enter $700 as the monthly contribution. The match is essentially free money — always contribute at least enough to capture the full match.
How does the 4% withdrawal rule work?
The 'Trinity Study' found that withdrawing 4% of your starting retirement corpus in year one, then adjusting for inflation annually, has historically survived 30 years of retirement with high probability (~95%) across a 50/50 stock-bond portfolio. This rule of thumb is a starting point; actual safe withdrawal rates depend on market conditions at retirement and your asset allocation.
Last updated: July 21, 2026 · Author: HT99 Tools Editorial Team · Reviewed by: HT99 Tools Editorial Team