What Is a Long-Term Part-Time Employee in a 401(k)?

Five hundred hours does not create immediate 401(k) eligibility.

Starting with plan years in 2025, the special LTPT route generally requires an employee to complete:

• two back-to-back 12-month periods
• with 500 or more hours of service in each
• and attain age 21 by the close of the second qualifying period.^[1][2][3]

That path operates alongside the traditional one-year-of-service route.

A 401(k) generally cannot delay an employee's right to make elective deferrals beyond the earlier of:

• the ordinary service period permitted under Section 410(a), commonly a 12-month period with 1,000 hours where the plan uses that method
• the special LTPT two-year 500-hour path.^[1][3]

The two clocks run at the same time.

Key Takeaways

• SECURE 2.0 shortened the LTPT sequence from three qualifying years to two for plan years starting after December 31, 2024.^[1][3][4]
• The two qualifying 12-month periods generally must be consecutive.
• Each period needs at least 500 hours.
• The worker generally must reach age 21 before the final qualifying period closes.^[1]
• The LTPT rules matter only when the employee becomes eligible solely because of the special 500-hour path.^[1]
• An employee who becomes eligible under a more generous plan provision can participate without technically being an LTPT employee.
• Entry after satisfying the LTPT requirements generally must occur no later than the earlier of the first day of the first plan year beginning after qualification or six months after qualification.^[1]
• A pre-eligibility year below 500 hours can break the sequence.
• After an employee actually qualifies as LTPT, a later year below 500 hours does not by itself remove deferral eligibility.^[1]
• LTPT status guarantees access to the elective-deferral feature, not automatically the same employer contribution package offered to every other participant.^[1]
• Matching and nonelective contributions can generally be omitted for LTPT employees under the special rules, subject to plan design and other applicable requirements.^[1]
• If the plan provides employer contributions, a 12-month period reaching 500 hours can count as a vesting year under the special rule.^[1]
• If the employee later satisfies ordinary eligibility without relying on the LTPT route, special LTPT testing exceptions generally end beginning with the following plan year, although the special vesting treatment can continue.^[1]

The Rule Changed From Three Years to Two

The original SECURE Act used:

three consecutive 12-month periods

with at least:

500 hours in each.^[1][5]

SECURE 2.0 shortened that sequence.

For plan years starting after:

December 31, 2024

the statutory service path generally became:

two successive 12-month periods, each reaching at least 500 hours.^[1][3][4]

The old three-year rule still matters historically because employees could first become eligible under it for 2024 plan years.

It is not the current service threshold for a 2026 calendar-year 401(k).

The 1,000-Hour Rule Did Not Disappear

The LTPT rule did not replace ordinary eligibility.

It added another route.

A plan using a traditional hours-based service condition can generally require no more than the earlier of:

Ordinary path

A 12-month period in which the employee completes the required year of service, commonly up to:

1,000 hours

LTPT path

Two back-to-back 12-month periods that each reach:

500 hours or more

plus the applicable age condition.^[1][3]

Whichever path is satisfied first controls the maximum permitted service delay.

Example: The 1,000-Hour Path Wins

Employee is hired January 1, 2026.

During 2026:

1,050 hours

The employee does not need to wait for a second 500-hour year merely because the person is part-time on the HR system.

The ordinary year-of-service path has already been satisfied.

The LTPT route is no longer the reason that employee enters the deferral feature.

Example: The LTPT Path Wins

Service record:

2025

620 hours

2026

650 hours

The employee never reaches 1,000 hours in either year.

But the worker has completed the required two-period sequence, and each period exceeds the 500-hour floor.

Assume the age requirement is satisfied.

The plan cannot continue waiting indefinitely for a future 1,000-hour year.

The special LTPT route has done its job.

LTPT Is a Technical Status, Not a Synonym for Part-Time

An employee can work part time without being an LTPT employee.

An employee can participate in a 401(k) while working part time and never become an LTPT employee.

Why?

Because Section 401(k)(15)'s special treatment applies to employees whose eligibility arises solely because of the special 500-hour route.^[1]

Suppose a plan allows everyone to defer immediately upon hire.

A new employee works 15 hours per week.

That employee is:

• part-time in ordinary language
• eligible for the plan

but is not relying on the LTPT service rule to become eligible.

The plan is simply more generous.

A More Generous Plan Can Make LTPT Status Irrelevant

Assume the plan requires:

500 hours in one 12-month period

for all employees.

An employee completes 600 hours in the first year.

The person enters because of the plan's own one-year 500-hour rule.

Such an employee is not technically LTPT because eligibility did not arise solely from completing the statutory number of consecutive 500-hour periods.^[1]

The employee still gets to participate.

The distinction matters for the special exclusions available only for actual LTPT employees.

Age 21 Still Matters

The employee generally must attain:

age 21

before the final required 12-month period closes.^[1]

Age and service therefore need to be tracked together.

Example: Hours Are Met Before Age 21

First measurement period:

June 1, 2025–May 31, 2026

600 hours

June 1, 2026–May 31, 2027

600 hours

Employee turns 21:

October 3, 2026

That occurs before the second period closes.

The age condition is satisfied by the end of the qualifying sequence.

Example: Turning 21 Too Late for That Sequence

Employee has two earlier 600-hour years.

During the next 12-month period, the employee turns 21 but works only:

400 hours

The earlier years do not automatically lock in eligibility.

The worker must reach age 21 no later than the end of the final 500-hour qualifying period.^[1]

A new qualifying sequence may be needed.

That is why HR should not track hours in one spreadsheet and age in another without joining the data.

The Measurement Period Is More Technical Than "Calendar Year"

The initial 12-month period generally begins when the employee first has an hour of service.^[1]

The plan can provide that later measurement periods shift to the plan year beginning within that initial period.^[1]

That can create overlap.

Example: Anniversary Year and Plan Year Overlap

Employee starts:

June 1, 2025

Initial measurement period:

June 1, 2025–May 31, 2026

Assume a calendar-year plan uses plan-year periods after the initial period.

A later measurement period can be:

January 1, 2026–December 31, 2026

Those periods overlap by five months.

That structure is permitted when the plan uses the applicable measurement method.^[1]

The overlap is not double employment.

It is a measurement convention.

A Sub-500-Hour Year Can Break the Sequence Before Eligibility

Suppose an employee works:

2024

700 hours

2025

450 hours

2026

700 hours

The worker does not have:

two consecutive qualifying periods

for the post-2024 LTPT route.

The 450-hour period breaks the chain.^[1]

The employee needs a later adjacent period that reaches the 500-hour minimum, assuming ordinary eligibility has not been reached first.

Example: 700, 450, 700, 650

Service:

• 2024: 700
• 2025: 450
• 2026: 700
• 2027: 650

The qualifying pair is:

2026 + 2027

not:

2024 + 2026

"Consecutive" matters.

A benefits system that only counts the number of years above 500 will get this wrong.

Once LTPT Eligibility Is Earned, a Slow Year Does Not Reset It

The rule changes after the worker becomes eligible.

An employee who has become eligible as LTPT does not lose that status merely because a later 12-month period contains fewer than 500 hours.^[1]

Example: 600, 650, Then 300

Employee completes:

• 2025: 600 hours
• 2026: 650 hours

The worker qualifies through the LTPT path.

During 2027:

300 hours

That later 300-hour year does not by itself erase the right to participate in the deferral arrangement.^[1]

The hours matter differently for vesting.

Eligibility and vesting should not be treated as the same clock.

Plan Entry Has Its Own Deadline

Satisfying the two-year service test does not mean the employee always starts deferring the next day.

Entry must occur no later than the earlier of:^[1]

1. the first day of the first plan year beginning after the employee satisfies the LTPT requirements
2. six months after the date the requirements are satisfied.

This prevents a plan with a distant annual entry date from adding another long delay.

Example: Six Months Controls

Calendar-year plan.

Employee satisfies the LTPT conditions:

June 30, 2026

Next plan year begins:

January 1, 2027

Six months after qualification:

December 30, 2026

The earlier date is:

December 30, 2026

Under the proposed rule, waiting until January 1 would be too late.

Example: Next Plan Year Controls

Employee qualifies:

November 15, 2026

Six months later:

May 15, 2027

Next plan year:

January 1, 2027

January 1 arrives first.

The plan must permit entry by that date under the proposed framework.^[1]

"Part-Time" Is Not a Permanent Exclusion

A plan cannot rely on labels alone to exclude workers indefinitely when the exclusion operates as a service condition:^[1][2]

• part-time
• seasonal.^[2]

A service-based label can become a proxy for an impermissible service condition.

If the real reason someone is excluded is:

"You never work 1,000 hours"

the LTPT rule exists to stop that exclusion from lasting forever.

A Genuine Non-Service Classification Can Be Different

A plan can impose a legitimate eligibility condition not based on age or service, such as certain job classifications, provided the condition is not a proxy for an impermissible service requirement.^[1]

Example:

Plan covers employees at:

Plant C

but not:

Plant D

That can be analyzed as a job/location classification rather than a disguised hours rule.

The plan still has to satisfy:

• Section 410(b) coverage
• other nondiscrimination requirements.

Writing a classification into the document does not make it automatically valid.

INV-089 covers coverage testing.

The LTPT Rule Guarantees Deferral Access, Not Automatically Employer Money

This is the most important economic distinction.

The statute generally permits a plan to give an LTPT employee elective-deferral access without requiring the employer to provide the same:

• matching contributions
• nonelective contributions

that it provides to other eligible employees.^[1]

That is part of the statutory LTPT design.

Example: Deferrals Allowed, Match Excluded

Plan provides ordinary eligible employees:

100% match on first 4% deferred

Employee enters solely through the LTPT rule.

The plan can, if its terms and applicable rules permit, allow the employee to defer while excluding that LTPT employee from the employer match.^[1]

The employee has gained access to the 401(k) savings mechanism.

Employer-funded economics can remain different.

Safe Harbor Does Not Automatically Erase the LTPT Exception

LTPT employees are coordinated with safe-harbor 401(k) and 401(m) rules under the applicable framework.^[1]

An employer can elect, subject to the regulatory framework, to exclude LTPT employees from specified safe-harbor and nondiscrimination provisions.

That can allow the plan to preserve safe-harbor treatment without making safe-harbor contributions for LTPT employees who are properly excluded under the special rule.^[1]

Do not simplify that to:

"Safe harbor means every LTPT gets the match."

Nor should it be simplified to:

"LTPTs never get safe-harbor contributions."

The plan document and employer elections matter.

SIMPLE 401(k) Is Different

SIMPLE 401(k) plans present a significant exception.^[1]

SIMPLE 401(k) plans have mandatory employer contribution structures.

The proposal would require applicable SIMPLE 401(k) employer contributions for LTPT employees rather than applying the ordinary exclusion in the same way.^[1]

That is one reason the phrase:

"LTPT employees never get employer contributions"

is wrong.

Plan type matters.

Employer Contributions Create a Vesting Question

If an LTPT employee receives employer contributions, the special vesting rule can be more favorable than a normal 1,000-hour vesting year.

For LTPT vesting, the statute generally treats a 12-month period reaching at least:

500 hours

as a year of vesting service for the applicable employer contributions.^[1]

That is a separate 500-hour use.

Do not confuse:

• 500-hour eligibility sequence
• 500-hour vesting year.

They interact but answer different questions.

Example: Employer Voluntarily Matches LTPT Employee

Employee qualifies as LTPT.

Plan chooses to provide a discretionary employer match.

Vesting schedule:

graded

Later service:

• 2026: 650 hours
• 2027: 550 hours
• 2028: 400 hours

Under the special vesting rule, the 650-hour and 550-hour periods can count as vesting years.

The 400-hour period generally does not create a 500-hour vesting year.^[1]

The contribution can be voluntary while the vesting treatment is still statutory.

Service Before 2021 Has Special Treatment

The SECURE Act excluded 12-month periods beginning before:

January 1, 2021

from the original LTPT eligibility count.^[1][5]

SECURE 2.0 also addressed vesting service.

Pre-2021 periods can generally be disregarded for LTPT vesting treatment under the applicable transition rules.^[1]

Historical service therefore needs more care than simply importing every year in the payroll archive.

LTPT Can Become Former LTPT

An employee does not necessarily stay in the special LTPT category forever.

Suppose the employee enters solely through the 500-hour route.

Later, that worker completes an ordinary year of service sufficient to satisfy the plan's normal eligibility rule without relying on LTPT.

Once ordinary eligibility is satisfied, the special LTPT treatment generally ends beginning with the first plan year after that year.^[1]

This person is treated as a:

former long-term, part-time employee.^[1]

Example: LTPT Then 1,000 Hours

Employee enters as LTPT for 2026.

During 2027, employee completes:

1,100 hours

and thereby satisfies the plan's ordinary eligibility path.

Beginning with the first plan year after the applicable transition point, the special LTPT exclusions generally stop applying.^[1]

The employee is no longer someone the employer can treat as LTPT merely because that was the original entry route.

Former LTPT Does Not Mean Service History Is Forgotten

The special testing and employer-contribution exclusions can end when the employee becomes former LTPT.

The special vesting rule can continue.^[1]

A former LTPT employee can continue receiving vesting credit for a qualifying 12-month period that reaches the 500-hour threshold.^[1]

That is easy to miss.

Status changes.

Vesting history does not reset.

A Later Sub-500 Year Is Not the Same as Becoming Former LTPT

An LTPT employee who later works:

350 hours

does not become former LTPT merely because the hours dropped.

The rules distinguish:^[1]

• failing to reach 500 hours in a later period
• satisfying ordinary eligibility
• ceasing to satisfy a genuine non-age/non-service plan condition.^[1]

Those events have different consequences.

Do not build payroll logic that automatically flips LTPT status off whenever annual hours fall below 500.

Coverage and Nondiscrimination Elections Matter

Qualifying LTPT employees may be excluded from specified testing provisions under the statutory election.

The available elections can affect:^[1]

• Section 410(b) coverage
• Section 401(a)(4) nondiscrimination
• ADP testing
• ACP testing
• certain safe-harbor provisions
• top-heavy requirements.

These exclusions depend on the employee actually being LTPT and on the plan/employer applying the rules consistently.

An Employee Who Was Never LTPT Cannot Be Excluded as LTPT

Suppose the plan provides immediate eligibility for all employees.

A part-time employee works:

• 600 hours in 2025
• 600 hours in 2026

The employee was already eligible.

The employer cannot later say:

"This person would have met the LTPT hours test, so the plan can now exclude the employee from testing as LTPT."

The special status depends on eligibility arising solely through the statutory route.^[1]

That is why generous eligibility can reduce administrative complexity but also changes which LTPT exceptions are available.

A Proxy Exclusion Can Cost the Employer the LTPT Testing Relief

Special rules apply when an employee otherwise would qualify as LTPT but is kept out through another plan condition.^[1]

If that condition is used in a way that does not satisfy the LTPT framework, the employer cannot assume it still receives all of the special LTPT testing exclusions.

This prevents a sponsor from taking both positions:

"The employee is too part-time to enter."

and:

"The employee is LTPT only when that status produces a better testing result."

Classification needs to be consistent.

LTPT and ADP Testing Pull in Opposite Directions

INV-087 explains ADP.

An LTPT employee who becomes eligible to defer but contributes:

0%

can reduce the NHCE ADP if the employee is included in the test.

The statutory election to remove LTPT employees from specified nondiscrimination testing can therefore materially affect the result.^[1]

That election can be especially relevant in industries with many low-hour employees.

The employer must follow the plan's legal testing framework rather than adjusting populations after seeing the result.

LTPT and Coverage Also Need Separate Thinking

INV-089 explains Section 410(b).

Eligibility for deferrals is not the same as entitlement to every employer contribution.

A plan can therefore have separate coverage questions for:

• elective-deferral arrangement
• match
• profit-sharing contribution.

LTPT status may solve one service-access issue while leaving another coverage analysis intact.

Part-Time Employees Can Break a Solo 401(k)

INV-030 explains one-participant 401(k)s.

An owner cannot preserve solo-plan treatment by saying:

"My employee is only part-time."

If a common-law employee satisfies:

• ordinary plan eligibility
• or the LTPT service route

the owner needs to evaluate plan coverage and one-participant status.

The solo label does not override federal eligibility rules.^[2][3]

Common-Law Employee Status Still Comes First

INV-093 explains worker classification.

The LTPT rule applies to:

employees

It does not automatically apply to a genuine independent contractor.

A worker paid on Form 1099 who is actually a common-law employee can create an LTPT issue.

A genuine independent contractor does not become a plan employee merely by working 500 hours for a client.

Hours come after classification.

Leased Employees Are a Separate Layer

INV-092 explains Section 414(n).

A statutory leased employee can be treated as an employee of the recipient for specified qualified-plan rules.

That can affect which service periods and populations need to be considered.

Do not use LTPT as a substitute for the leased-employee analysis.

The order remains:

1. identify employee status
2. identify employer or related-employer group
3. apply plan eligibility rules
4. apply LTPT if the special service path is relevant.

403(b) Plans Now Have Their Own LTPT Layer

SECURE 2.0 extended ERISA long-term part-time rules to certain 403(b) plans starting with plan years after 2024.^[4]

IRS Notice 2024-73 addresses discrete 403(b) nondiscrimination issues.^[4]

That does not make every 403(b) rule identical to the 401(k) rule.

This article focuses on 401(k) plans.

Sponsors administering both plan types should not copy one eligibility file into the other without checking the separate statutory and regulatory framework.

A Missed LTPT Entry Is a Plan Failure

Plan sponsors should identify employees who have not entered under the ordinary service rule and determine whether the LTPT pathway applies.^[2]

If an eligible worker was not timely allowed to make an elective-deferral election, the employer can have a plan qualification failure.^[2][6]

Correction can involve the current EPCRS rules.

Correction Is Not Just "Open the Account Now"

When an eligible employee was wrongly excluded, correction can require:^[6][7]

• missed elective-deferral opportunity
• missed employer match
• missed nonelective contribution
• earnings
• timing of correction
• whether special correction relief applies.

The correct amount depends on the plan and current correction procedure.

Do not use a generic percentage copied from an old plan memo.

The Census Control That Actually Works

For every employee below ordinary eligibility, track:

The key is not the annual total.

It is the sequence.

Frequently Asked Questions

Who qualifies as an LTPT employee in a 401(k)?

An LTPT employee is generally someone who becomes eligible to make 401(k) elective deferrals solely because the special Section 401(k) service rule is satisfied rather than the plan's ordinary eligibility path.^[1]

How many years of 500 hours are required in 2026?

For plan years starting in 2025 or later, generally two consecutive 12-month measurement periods, each with 500 or more credited hours.^[1][3][4]

Is the old three-year rule gone?

It remains relevant historically for eligibility arising before 2025, but SECURE 2.0 reduced the sequence to two years once plan years moved past December 31, 2024.^[1][3]

Does 500 hours in one year make me eligible?

Not under the federal LTPT rule by itself. A plan can be more generous, but the statutory LTPT route generally requires two consecutive qualifying periods after 2024.^[1]

Does the employee have to be age 21?

The LTPT statutory framework generally requires the employee to reach age 21 by the end of the final qualifying 12-month period.^[1]

What if I work 1,000 hours before completing the LTPT sequence?

You can satisfy the ordinary service path first. The plan generally cannot force you to wait for the LTPT sequence when the ordinary eligibility requirement has already been met.^[1][3]

When must the plan let an LTPT employee start deferring?

No later than the earlier of the first day of the first plan year after qualification or six months after the qualification date.^[1]

Does a year below 500 hours break the sequence?

Before LTPT eligibility is established, it can prevent earlier years from forming the required consecutive sequence.^[1]

What if hours fall below 500 after I already became LTPT?

That later low-hour period does not by itself erase LTPT participation eligibility.^[1]

Must an LTPT employee receive the employer match?

Not automatically. The special rules generally allow the employer to exclude LTPT employees from matching and nonelective contributions, subject to plan terms and other applicable requirements.^[1]

Do safe-harbor 401(k)s have to make safe-harbor contributions for LTPT employees?

Special employer elections coordinate LTPT employees with ADP/ACP safe-harbor requirements. The answer depends on the plan's elections and design; safe-harbor status alone does not create a universal yes or no.^[1]

Do LTPT employees get vesting credit?

For applicable employer contributions, the special rule generally awards one vesting year when a 12-month measurement period reaches 500 hours.^[1]

What happens after an LTPT employee later works 1,000 hours?

If that year causes the employee to satisfy ordinary eligibility without relying on the LTPT route, the person generally moves into former-LTPT treatment beginning with the following plan year, while the special vesting rule can continue.^[1]

Can a plan exclude part-time employees as a class?

A plan cannot use a part-time or seasonal label as a proxy for a service condition that defeats the LTPT requirement. A genuine non-service classification can be permitted, but it still must satisfy Section 410(b) and other qualification rules.^[1][2]

Do LTPT rules apply to independent contractors?

Not merely because they work 500 hours. Employee classification comes first. A genuine independent contractor is not converted into a 401(k) employee by the LTPT hour threshold.

What if the employer missed an LTPT employee?

The employer should apply the current IRS correction procedures to the facts. A missed opportunity to make elective deferrals can be a plan qualification failure requiring more than prospective enrollment.^[2][6][7]

The Five-Date Test

For each low-hour employee, pull five dates:

1. employment commencement date
2. date first qualifying 500-hour period ends
3. date second consecutive qualifying period ends
4. 21st birthday
5. required plan entry date

Then check whether a 1,000-hour ordinary year occurred first.

That sequence answers most LTPT eligibility questions faster than the employee's label does.

Part-time is a payroll description.

LTPT is a statutory status created by a specific service path.

Sources & References

1. IRS/Treasury: REG-104194-23 — Long-Term, Part-Time Employee Rules Under Section 401(k) (88 FR 82796)
2. IRS: Employee Plans News — Long-Term Part-Time Employees in 401(k) Plans
3. IRS Publication 560: Retirement Plans for Small Business
4. IRS Notice 2024-73: Additional Guidance With Respect to Long-Term, Part-Time Employees
5. IRS: Operational Compliance List
6. IRS: 401(k) Fix-It Guide — Eligible Employees Were Not Given the Opportunity to Make Elective Deferrals
7. IRS: EPCRS Overview
8. U.S. Department of Labor: SECURE Act

Educational Disclaimer

ROIStreet publishes educational content about retirement-plan eligibility and administration. This article is not legal, tax, employment, fiduciary or plan-administration advice. LTPT eligibility depends on plan terms, service-crediting method, employee status, age, measurement periods, employer elections and current law.

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