For a 403(b) plan, includible compensation is the pay figure the IRS uses to cap how much can go into your account each year. It’s your gross compensation from an eligible 403(b) employer over your most recent one-year period of service, with several pre-tax salary reductions added back in and employer contributions left out. That number sets the 100% ceiling in the annual addition rule: for 2026, total contributions to your account cannot exceed the lesser of $72,000 or 100% of your includible compensation.1Internal Revenue Service. Notice 2025-67
The definition comes from Section 403(b)(3) of the Internal Revenue Code.2Office of the Law Revision Counsel. 26 USC 403 – Taxation of Employee Annuities Only pay from a qualifying employer counts, meaning a public school, a 501(c)(3) organization, or another entity authorized to sponsor a 403(b) plan.3Internal Revenue Service. IRC 403(b) Tax-Sheltered Annuity Plans Wages you earned from a non-qualifying employer, including a for-profit affiliate of a hospital or university, are excluded entirely.
Pay That Counts
Start with your gross income from the eligible employer. That includes base salary, wages, bonuses, commissions, and professional fees — the ordinary W-2 numbers.
Then add back the pre-tax amounts the statute specifically lists, so that saving for retirement or paying for benefits through payroll deduction doesn’t shrink the base:
- Elective deferrals to a 403(b), 401(k), SARSEP, or SIMPLE plan.2Office of the Law Revision Counsel. 26 USC 403 – Taxation of Employee Annuities
- Salary redirected into a Section 125 cafeteria plan for health, dental, or dependent care coverage.
- Qualified transportation fringe amounts excluded from gross income under Section 132(f)(4), such as transit passes or parking.
- Amounts deferred into an employer’s Section 457(b) deferred compensation plan.
Without these add-backs, a teacher deferring $24,500 into a 403(b) would appear to have $24,500 less in compensation, shrinking the 100% limit and creating a circular squeeze on future contributions.
Pay That Doesn’t Count
Two categories are excluded, and mixing them in is what usually produces excess contributions.
Contributions your employer makes on your behalf are not part of your includible compensation. The statute draws a clean line between what you earn and what the employer puts into the plan for you.2Office of the Law Revision Counsel. 26 USC 403 – Taxation of Employee Annuities Employer contributions still count against the $72,000 annual addition ceiling; they simply don’t inflate the compensation figure that sets that ceiling.
Wages from any period when your employer was not an eligible 403(b) sponsor are also ignored. If you transferred from a for-profit subsidiary into the tax-exempt parent mid-year, only the pay earned after you joined the qualifying employer belongs in the calculation.
The Most Recent Year of Service
Includible compensation is measured over a specific window: your most recent period of employment that adds up to one year of service. That period must end no later than the close of your taxable year, and it can’t reach back more than five years before the current taxable year.2Office of the Law Revision Counsel. 26 USC 403 – Taxation of Employee Annuities
For a full-time employee who worked the whole calendar year, this is straightforward. The measurement window is the current calendar year, and the pay earned during it is your includible compensation. Someone who started mid-year uses the months worked so far, which may not yet amount to a full year of service.
Part-Time and Fractional Service
If you work less than full-time, your “year of service” takes longer than one calendar year to accumulate. The fraction is your schedule compared to the employer’s definition of full-time. A teacher working three days a week at a school where full-time is five days earns three-fifths of a year of service each calendar year.
Consecutive fractional periods stack until they add up to one full year. For the three-fifths teacher, that’s roughly 20 months of calendar time. The pay earned across the combined window is the includible compensation figure.4eCFR. 26 CFR 1.403(b)-4 – Contribution Limitations Accurate timekeeping matters, because an incorrectly recorded fraction produces an incorrect contribution ceiling that’s hard to catch later.
When Compensation Keeps Running After You Stop Working
Several rules preserve or extend includible compensation past the point where a normal paycheck would end.
Disability
If you become permanently and totally disabled while employed by the plan sponsor, Section 415(c)(3)(C) lets your compensation be deemed to continue at the rate you were paid immediately before the disability.5Office of the Law Revision Counsel. 26 USC 415 – Limitations on Benefits and Contribution Under Qualified Plans Any employer contributions made under this provision must be immediately vested.
Military Differential Wages
If your civilian employer pays differential wages while you’re on active military duty, those payments are treated as wages under Section 3401(h), and IRS guidance confirms they are included in 403(b) compensation.6Internal Revenue Service. 403(b) Plan Listing of Required Modifications (LRM)
Post-Severance Pay
Compensation paid shortly after you leave the job can still count if it represents pay for services already performed. Final paychecks, accrued vacation payouts, and back pay are the common examples. These amounts still have to trace to your most recent year of service.7Internal Revenue Service. 403(b) Plan Fix-It Guide – Post-Severance Provision
The Five-Year Former Employee Rule
If the plan permits it, a former employer can keep making nonelective contributions to your 403(b) for up to five taxable years after you leave.8Internal Revenue Service. Retirement Plans FAQs Regarding 403(b) Tax-Sheltered Annuity Plans Your includible compensation is deemed to continue during that window at one-twelfth of your most recent year-of-service compensation for each month.4eCFR. 26 CFR 1.403(b)-4 – Contribution Limitations Three restrictions apply: contributions must be nonelective (no salary deferrals as a former employee), they can’t come from money otherwise payable to you, and they stop immediately at death.
How Includible Compensation Sets Your Contribution Limits
Two federal limits sit on top of every 403(b) account, and includible compensation anchors both.
The Section 415(c) annual addition limit caps everything flowing into the account in a year: your elective deferrals, employer matching, employer nonelective contributions, and after-tax contributions combined. For 2026, that cap is the lesser of $72,000 or 100% of your includible compensation.1Internal Revenue Service. Notice 2025-67 If your includible compensation is $60,000, the effective ceiling is $60,000, not $72,000.
The Section 402(g) elective deferral limit caps only the salary you personally defer. For 2026 it’s $24,500, and it applies across all your 403(b) and 401(k) plans combined.9Internal Revenue Service. Retirement Topics – 403(b) Contribution Limits Catch-up contributions available at age 50, at ages 60 through 63 under SECURE 2.0, and after 15 years of service with the same qualifying employer can stack on top of the base deferral limit under separate rules, but the combined total still has to fit within the 100%-of-includible-compensation ceiling.10Internal Revenue Service. 403(b) Plans – Catch-Up Contributions
What Goes Wrong When the Number Is Off
An inflated includible compensation figure produces an inflated contribution ceiling, and the correction rules aren’t gentle.
Excess elective deferrals over the Section 402(g) limit must be distributed by April 15 of the following year. Miss that deadline and the excess is taxed twice: once in the year earned and again when distributed from the plan.11Internal Revenue Service. Consequences to a Participant Who Makes Excess Annual Salary Deferrals
Excess annual additions over the Section 415(c) limit have to be corrected by the plan, usually by transferring the excess to a separate account or distributing it.12Internal Revenue Service. 403(b) Plan Fix-It Guide If your 403(b) is held as a custodial account invested in mutual funds under Section 403(b)(7)(A), an uncorrected excess is also subject to a 6% excise tax each year it remains in the account; the tax doesn’t apply to 403(b) annuity contracts.13Office of the Law Revision Counsel. 26 USC 4973 – Tax on Excess Contributions to Certain Tax-Favored Accounts
Most excess contribution problems trace back to a bad compensation figure at the start of the year. Confirm the add-backs, exclude employer contributions and non-qualifying wages, and check that the measurement window actually represents one year of service. Getting the number right up front is far cheaper than fixing it after.