The TaxAct program does not provide Alerts regarding the limits on deferred income as there are many situations where the limits may vary. This is outlined in detail in IRS Publication 525 Taxable and Nontaxable Income. Your employer or plan administrator should apply the proper annual limit when figuring your plan contributions; however, you are ultimately responsible for ensuring they are correct.

Per IRS Publication 525, on page 9:

Retirement Plan Contributions

Your employer's contributions to a qualified retirement plan for you aren’t included in income at the time contributed. (Your employer can tell you whether your retirement plan is qualified.) However, the cost of life insurance coverage included in the plan may have to be included.

If your employer pays into a nonqualified plan for you, you must generally include the contributions in your income as wages for the tax year in which the contributions are made. However, if your interest in the plan isn't transferable or is subject to a substantial risk of forfeiture (you have a good chance of losing it) at the time of the contribution, you don't have to include the value of your interest in your income until it's transferable or is no longer subject to a substantial risk of forfeiture.

TIP: For information on distributions from retirement plans, see Pub. 575 (or Pub. 721 if you’re a federal employee or retiree).

Elective Deferrals If you’re covered by certain kinds of retirement plans, you can choose to have part of your compensation contributed by your employer to a retirement fund, rather than have it paid to you. The amount you set aside (called an elective deferral) is treated as an employer contribution to a qualified plan. An elective deferral, other than a designated Roth contribution (discussed later), isn't included in wages subject to income tax at the time contributed. However, it’s included in wages subject to social security and Medicare taxes.

Elective deferrals include elective contributions to the following retirement plans.

1. Cash or deferred arrangements (section 401(k) plans).
2. The TSP for federal employees.
3. Salary reduction simplified employee pension plans (SARSEP plans).
4. Savings incentive match plans for employees (SIMPLE plans).
5. Tax-sheltered annuity plans (section 403(b) plans).
6. Section 501(c)(18)(D) plans. (But see Reporting by employer, later.).
7. Section 457 plans.

Overall limit on deferrals. For 2020, you shouldn't have deferred more than a total of $19,500 of contributions to the plans listed in (1) through (3), earlier, unless you are 50 or older. The specific plan limits for the plans listed in (4) through (7), earlier, are discussed later. Amounts deferred under specific plan limits are part of the overall limit on deferrals.

[The publication continues with the limitations based on specific circumstances.]

Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.