401(k) eligibility and entry date calculator.
Estimate when an employee meets the plan's minimum age and service requirements, and the first entry date after that. Enter the date of birth, date of hire, the requirements and the plan's entry schedule.
Illustrative estimates only. Results do not determine eligibility, legal compliance, tax treatment or required corrective action.
Eligibility & entry-date checker
Estimate a potential eligibility date and next plan entry date from configurable age, service, and entry-frequency assumptions.
Age is measured from the date of birth; service is approximated as calendar months from hire. Actual plan language, hours-of-service/elapsed-time rules, break-in-service rules, and statutory eligibility restrictions are not modeled.
Preliminary workflow estimate only.
The math behind the result
Age requirement date
Date of birth plus the minimum age.
Service requirement date
Date of hire plus the service requirement in calendar months.
Eligibility date
The later of the age date and the service date.
Entry date
The first entry date on or after eligibility: immediate, the first of any month, quarterly (January, April, July, October), semiannual (January and July) or annual (January 1).
Good uses
- Answering a sponsor's question about when a new hire can join
- Checking census data for employees who should have been offered entry
- Explaining how a change of entry schedule affects participation timing
What it does not do
- Service is approximated as calendar months; hours-of-service, elapsed-time and break-in-service rules are not modeled
- Long-term part-time employee rules under SECURE and SECURE 2.0 are not modeled
- The plan document controls; statutory maximums limit how restrictive a plan can be
Frequently asked questions
What is the most restrictive eligibility a 401(k) can use?
In general, a plan can require employees to be age 21 and complete one year of service, and must let them enter no later than the earlier of the first day of the next plan year or six months after meeting the requirements. Long-term part-time rules can require earlier entry for deferrals.
Why does the entry schedule matter?
With semiannual entry, an employee who becomes eligible in February waits until July; with monthly entry they join the next month. The schedule changes both participation and testing results.
Does the calculator handle long-term part-time employees?
No. Under SECURE 2.0, employees with two consecutive years of at least 500 hours generally become eligible to defer for plan years beginning in 2025 and later. Check those employees separately.
Related tools and guides
Census validation tool
Upload a synthetic or de-identified 401(k) census CSV and get an instant exception report. Processing stays in your browser; nothing is sent to a server.
ADP/ACP test estimator
Free online ADP and ACP test calculator: compare HCE and NHCE average deferral and contribution percentages against the basic nondiscrimination limits.
Employer match estimator
Model a two-tier 401(k) employer match, such as 100% of the first 3% plus 50% of the next 2%, and see the match in dollars and as a percent of pay.
See this work inside the pilot build.
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