403(b) Calculator: How to Use It

What this calculator does

The 403(b) calculator projects the future value of your account at retirement using the standard compound growth formula applied to your current balance, annual contributions, employer match, and expected return over your chosen time horizon. It shows the split between what you contributed versus what the market added, and estimates the monthly income a 4% withdrawal rate would generate from the projected balance.

All figures are in nominal (not inflation-adjusted) dollars. The calculator doesn't model taxes on withdrawal, Roth conversions, or required minimum distributions after age 73.

What each input means

Current 403(b) balance

Your account balance today before this year's contributions. Find it on your most recent account statement or by logging into your plan provider. If you have multiple 403(b) accounts from prior employers, you can add them together or run separate projections. This balance compounds from day one regardless of new contributions: a $50,000 balance growing at 6% for 25 years becomes roughly $215,000 without adding a single new dollar.

Annual contribution

The total dollar amount you contribute per year. The 2026 IRS limits are:

• Under age 50: $24,500
• Age 50 to 59: $32,000 (standard $7,500 catch-up)
• Age 60, 61, 62, or 63: $35,750 (enhanced SECURE 2.0 catch-up of $11,250)
• Age 64 and older: $32,000 (reverts to standard $7,500 catch-up)

Enter the dollar amount, not the percentage of your salary. If your contribution is 6% of a $72,000 salary, enter $4,320. The calculator flags any entry over $24,500 if you haven't enabled a catch-up provision, since that would exceed the IRS limit for employees under 50.

Employer match (per year)

The flat dollar amount your employer contributes annually. Many school districts and nonprofits offer a fixed match rather than a percentage. Enter whatever your employer actually contributes, or leave it at $0. The compounded value of the employer match is shown separately in results so you can see exactly what you'd leave on the table by contributing below the match threshold.

Years until retirement

How many full years you plan to keep contributing. The calculator applies your annual contributions for exactly this many years, then stops. A rough sense of the math: at 6%, each additional year of contributions adds roughly one year's contribution plus the growth that money earns over the remaining period. Each additional year of compounding on the existing balance adds about 6% to whatever is already there.

Expected annual return

The assumed annual rate of return on your investments. The S&P 500 has returned roughly 10% per year nominally since 1926, about 7% after inflation. A diversified stock and bond portfolio typically lands between 5% and 7% real. The default of 6% is a conservative middle estimate. 403(b) investment menus vary widely; plans at large school districts often include low-cost index funds, while older plans at small nonprofits may still offer only higher-fee annuity products. Subtract your average expense ratio from your expected gross return before entering it.

15-year catch-up toggle

A provision specific to 403(b) plans. If you've worked for the same qualifying employer (public school, 501(c)(3) nonprofit, hospital, or church) for at least 15 years, and your average annual contribution over that tenure has been below $5,000, you may contribute an additional $3,000 per year. The IRS caps the total amount ever used under this provision at $15,000 lifetime, spread across as many years as the math allows.

Not every plan supports the 15-year rule even when you technically qualify. Confirm with your HR department or plan administrator before relying on it. When enabled, the calculator adds $3,000 to your annual contribution total for the full projection period. Adjust if you've already used some of the $15,000 lifetime limit.

Understanding the outputs

Projected balance at retirement

The future value of your account calculated using the standard compound growth formula: FV = PV x (1 + r)^n + PMT x ((1 + r)^n - 1) / r. PV is your current balance, r is the annual return, n is years to retirement, and PMT is total annual contributions including employer match and any catch-up amounts. Contributions are assumed to be made once per year at the start of each period.

Monthly income at 4% withdrawal

Your projected balance times 4%, divided by 12. The 4% figure comes from the 1998 Trinity Study (Cooley, Hubbard, and Walz at Trinity University), which analyzed historical portfolio survival rates and found that a 4% annual withdrawal had a high probability of lasting 30 years through every historical market cycle since 1926. It's a starting point for planning, not a guarantee. If you expect a 35 or 40-year retirement, some planners use 3.5%. If you have significant other income (a pension, Social Security), 4.5% or more may be defensible for the portion from your 403(b).

Contributions vs. growth breakdown

The stacked bar splits your projected balance into money you put in (contributions plus employer match plus starting balance) and money the market added. At 6% for 30 years, a dollar invested today grows to roughly $5.74, so about 83% of the ending value comes from growth rather than contributions. This ratio is why the starting balance and early contributions matter so much more than late contributions, and why a higher expense ratio is so costly over time.

Employer match value

The difference between your projected balance with the employer match and without it. If your employer contributes $2,000 per year for 25 years at 6%, the compounded value of that match alone is over $109,000. That's the dollar amount you'd forfeit by contributing below the match threshold or by choosing the Investment Plan over the Pension Plan if both offer employer contributions.

403(b) vs 401(k): what's actually different

The contribution limits are identical. Both allow traditional pre-tax and Roth after-tax contributions. Both have the same early withdrawal penalty rules. The key differences are who offers them (nonprofits and public schools for 403(b), private employers for 401(k)), what investments are available (403(b) plans historically limited to annuities and mutual funds, though most modern plans have broader menus), and the 15-year catch-up rule, which is exclusive to 403(b) plans with no equivalent in 401(k) plans.

If you work at a hospital or university that offers both a 403(b) and a 457(b), the limits are completely separate. You can max both in the same year, putting up to $49,000 in combined deferrals if you're under 50, or more with applicable catch-ups. That dual-limit opportunity doesn't exist with a 403(b) and a 401(k) at different employers, where the $24,500 limit is shared.