Retirement Calculator
Model future portfolio values, safe withdrawal rates, and post-career financial independence.
Parameters & Inputs
Summary & Breakdown
Portfolio Growth Trajectory
About the Retirement Calculator
Planning for retirement requires understanding how consistent monthly contributions compound over decades. Small habits in your twenties and thirties provide massive exponential benefits due to the time value of money.
This retirement calculator models your projected nest egg based on your current savings balance, recurring monthly deposits, and expected investment growth rates.
It also applies the recognized 4% Safe Withdrawal Rate (SWR) rule of thumb to estimate your sustainable monthly cash flow after leaving the workforce.
How the Calculations Work
Calculations model future value combining lump-sum starting savings growth and regular monthly annuity compounding over the working years.
FV = P(1 + r/12)^(12t) + PMT * [((1 + r/12)^(12t) - 1) / (r/12)], Annual Income = FV * SWR%
Variables & Definitions
- FV: Future retirement portfolio value
- P: Current initial savings
- PMT: Monthly contribution deposit
- r: Annual investment return rate (decimal)
- t: Years remaining until retirement (Retire Age - Current Age)
Starting at age 30 with $50,000, retiring at 65 (t = 35 years), saving $750 monthly at 7.5% annual return: After 35 years, total portfolio compounds to $2,077,419. At a 4% safe withdrawal rate, this delivers $83,097 annually or $6,925 monthly in retirement income.
Key Terms Explained
Safe Withdrawal Rate (SWR)
The percentage of your portfolio you can withdraw annually without running out of money across a 30-year retirement.
Nest Egg
The total accumulated retirement portfolio across 401(k), IRA, pension, and brokerage accounts.
Compound Growth
The returns earned on previous returns that accelerate portfolio growth exponentially over long horizons.
Sequence of Returns Risk
The danger that market downturns early in retirement disproportionately impair portfolio longevity.
Practical Tips & Pitfalls to Avoid
Capture full employer 401(k) matches
Employer match is an instantaneous 100% guaranteed return on investment.
Increase contributions annually
Commit 50% of every future salary raise directly to retirement savings.
Diversify across tax buckets
Balancing Traditional (pre-tax) and Roth (tax-free) accounts provides tax flexibility in retirement.
Adjust risk with age
Gradually shift from aggressive growth equities toward fixed income as you approach your target retirement year.
Frequently Asked Questions
Derived from the Trinity Study, it states that withdrawing 4% of your balanced portfolio in year 1 and adjusting for inflation annually historically survives 30 years in 95% of market conditions.
A common guideline is having roughly 1x your annual salary saved by 30, 3x by 40, and 6x by 50.
Historical US stock market long-term returns average 7% to 10% before inflation. Modeling with 6% to 8% is prudent for diversified portfolios.
You can model real purchasing power by using an inflation-adjusted return (e.g. 7% nominal return minus 2.5% inflation = 4.5% real return).
Retiring earlier increases the duration your portfolio must sustain, typically requiring a slightly lower withdrawal rate like 3.25% to 3.5%.