403(b) Calculator

Understanding 403(b) Retirement Plans

A 403(b) plan, also called a Tax-Sheltered Annuity (TSA), is an employer-sponsored retirement account available to employees of qualified nonprofit organizations, public schools, government agencies, hospitals, and religious institutions. Unlike 401(k) plans offered by for-profit companies, 403(b) plans are specifically designed for public-sector and tax-exempt workforce members.

The core mechanism is straightforward: contributions are deducted from your paycheck before tax is applied, reducing your taxable income in the contribution year. Your money then grows tax-deferred inside the account until withdrawal, typically at retirement. Many 403(b) plans offer employer matching contributions—commonly 50% of your contribution up to a percentage of base salary—effectively providing immediate returns on your savings.

Investment options in 403(b) accounts are more limited than 401(k) plans. You can typically choose from mutual funds and annuities selected by your plan sponsor, rather than the 20+ options sometimes available in 401(k) accounts. This simplification can be helpful for those who prefer a curated selection.

403(b) Contribution Limits and Eligibility Rules

For 2024, the standard annual elective deferral limit is $23,500 for employees under age 50. Those 50 and older can contribute an additional $7,500 catch-up amount, bringing their total to $31,000.

A distinctive 403(b) feature is the 15-year service catch-up provision. If you have at least 15 years of service at a qualified organization and have not maximized catch-up contributions in prior years, you may be eligible to contribute an extra $3,000 per year (lifetime cap of $15,000) beyond standard limits. This can raise your maximum contribution to $29,000 annually, or $36,500 if you're 50+ and use both catch-up options.

Most employers set a default contribution rate around 5% of base salary for new participants, though you can adjust this percentage at any time. Some plans also offer Roth 403(b) options, where contributions are made with after-tax dollars but grow and are withdrawn tax-free—a valuable choice if you expect higher tax brackets in retirement.

How the 403(b) Balance Grows

Your 403(b) balance compounds based on four key variables: your annual contribution amount, your employer's match, the investment return rate, and time. The calculator uses these relationships to project your balance forward:

• Salary — Your current annual gross income, which forms the base for calculating contribution amounts.
• Employee Contribution Percentage — The percentage of your salary you elect to defer into the 403(b) account each pay period.
• Employer Contribution Percentage — The percentage of your salary your employer contributes on your behalf, often via a matching program.
• Annual Rate of Return — Your expected net investment return, adjusted downward for management fees and expense ratios.
• Annual Salary Growth — The percentage rate at which you expect your salary to increase each year, which raises future contributions.
• Current Balance — Your existing 403(b) account balance at the start of the projection period.
• Years Until Retirement — The number of years from now until your intended retirement age, determining the compounding period.

Common Pitfalls When Planning Your 403(b)

Avoid these frequent mistakes to maximize your retirement readiness.

1. Underestimating the impact of employer match — Many employees contribute below the employer match threshold and leave free money on the table. If your employer matches 50% of contributions up to 6% of salary, contributing less than 6% means you're forgoing immediate 50% returns on that portion. Prioritize reaching the full match before other financial goals.
2. Neglecting salary growth in projections — If you expect regular raises over your career, your contributions will naturally increase in absolute dollars even if your percentage stays constant. This accelerates compound growth significantly. The calculator accounts for this with an annual salary increase percentage—being realistic here prevents overestimating or underestimating your final balance.
3. Confusing pre-tax and Roth contributions — Traditional 403(b) contributions lower your taxable income now but are taxed as ordinary income on withdrawal. Roth contributions are taxed now but withdrawn tax-free. If you expect to be in a higher tax bracket at retirement, Roth contributions may be superior. Some plans allow both in the same year—splitting contributions can optimize your tax position.
4. Using overly optimistic return assumptions — Historical stock market averages around 10% nominal annually, but your actual net return depends heavily on fees, asset allocation, and market timing. A 7–8% assumption after fees is more conservative and realistic. Plugging in 12% or higher often leads to retirement shortfalls when actual returns disappoint.

403(b) vs. 401(k): Key Differences

While 403(b) and 401(k) plans operate on similar tax-deferred principles, several distinctions matter for planning purposes:

• Sponsorship and eligibility: 401(k) plans are for employees of for-profit companies; 403(b) plans serve nonprofit and public-sector workers.
• Investment options: 401(k)s typically offer 15–25 investment choices; 403(b)s are limited to mutual funds and annuities chosen by the plan sponsor.
• Contribution limits: Both have the same standard limits ($23,500 for 2024), but 403(b) adds the unique 15-year service catch-up of up to $3,000 annually.
• Withdrawal rules: 403(b) plans often allow loans and may offer more flexible withdrawal provisions, depending on the plan document.
• Portability: 401(k) balances transfer more easily between employers; 403(b) transfers can be more complex and depend on the annuity or custodian.

If you're comparing retirement strategies across account types, consider how a 403(b) plus an IRA might complement each other. You can contribute to both in the same year, up to their respective annual limits.