403(b) Calculator
Contribution growth plus the 403(b)-specific 15-years-of-service catch-up for school, hospital, and nonprofit employees.
Your 403(b) Calculator Result
Generated from the inputs below — a record you can revisit, or share with anyone helping you plan.
Your detailsInput Parameters
Contribution
e.g. 50 means the employer matches 50 cents per dollar.
Catch-Up Eligibility
Drives the age-based catch-up (50+, and the higher SECURE 2.0 band at 60–63).
Only available at qualified organizations — schools, hospitals, home health agencies, health/welfare agencies, and churches — and only if the plan document allows it. Check with your plan administrator.
Growth
20 years of $7,875/year (employee + employer) growing at 7.0%, starting from $40,000.
8% of your $75,000 salary.
$24,500 base.
50% match on contributions up to 5% of salary.
Your contribution plus the employer match.
Analysis
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Open calculatorOverview
The 403(b) Calculator projects how your money grows over time when combined with regular contributions and compound returns. It provides instant, accurate results and helps you model scenarios so you can make better decisions with your money.
Compound interest is what Einstein allegedly called "the eighth wonder of the world." Whether you're saving for a home, retirement, or financial independence, the math is the same: time in the market beats timing the market. Small, consistent contributions over decades produce wealth that seems impossible with mental arithmetic.
The Math Behind the Calculation
Future value of a series of regular contributions (annuity due) plus an initial lump sum:
- FV — future value
- P — initial principal
- PMT — periodic contribution
- r — periodic rate of return
- n — number of periods
We assume contributions happen at the start of each period. Historical US stock market returns from 1957–2023 average about 10% nominal and 7% real (inflation-adjusted), per NYU Stern historical data. Your calculator lets you adjust this assumption.
How to Use This Calculator
- Enter your starting balance — current savings or $0 if starting fresh.
- Set a monthly contribution — what you realistically plan to invest each month. Even $50 matters.
- Choose a rate of return — 7% is a reasonable long-term stock-heavy portfolio assumption; 4% for bonds; 10% for aggressive all-equity.
- Set your time horizon — how many years until you need the money.
- Review the projection — look at the graph showing contributions vs. growth to see how compounding accelerates.
Understanding Your Results
- Future value — the projected total at the end of your time horizon.
- Total contributions — how much of that money came from your pocket.
- Interest earned — how much came from compounding. At long horizons, this dwarfs your contributions.
- Year-by-year breakdown — the growth curve steepens dramatically in later years, which is why starting early matters more than contributing more.
Practical Tips to Maximize Growth
- Use tax-advantaged accounts first. 401(k) with employer match is literally free money — always contribute at least enough to capture the full match. Roth IRAs grow tax-free.
- Automate it. Set up automatic transfers on payday so you never see the money. Behavioral studies show this dramatically improves savings rates.
- Don't pick individual stocks. Low-cost index funds (Vanguard VTI, Fidelity FSKAX, Schwab SWTSX) beat 90% of active managers over 15-year periods, per S&P SPIVA reports.
- Rebalance annually. Set target allocations (e.g., 80/20 stocks/bonds) and rebalance once a year to stay on plan.
- Increase contributions yearly. Even a 1% annual increase compounds massively over 30 years.
Frequently Asked Questions
What rate of return is realistic?
For a diversified US stock portfolio, 7% real (inflation-adjusted) or 10% nominal over 20+ year horizons is defensible based on historical data. Shorter horizons are much less predictable. Don't use 12% — that's a sales pitch, not a math-based assumption.
How does inflation affect my results?
A "nominal" return of 7% over 30 years with 3% inflation leaves you with only ~4% real purchasing power growth. Always think in real returns when planning for goals decades away. This calculator lets you model inflation separately.
Should I invest a lump sum or dollar-cost average?
Lump-sum investing has historically beaten dollar-cost averaging more often than not, because markets have tended to rise. DCA is a behavioral tool for people who can't emotionally handle putting a large sum in all at once.
What about taxes on growth?
In a taxable brokerage account, you'll owe capital gains tax on growth (15%–20% long-term federal for most people). In a Roth IRA/401(k), growth is tax-free. In a traditional IRA/401(k), you defer taxes and pay at withdrawal. Use our Roth vs Traditional IRA calculator to compare.