Every major decision in a 401(k) is tied to your age. Federal law sets the 401(k) age requirements that control when you can join a plan, when you can contribute extra, when you can withdraw without a penalty, and when you must start taking money out. The main thresholds are 21 to enter a plan, 50 to make catch-up contributions, 59½ for penalty-free withdrawals, 55 in some separation-from-service situations, and 73 for required minimum distributions (rising to 75 in 2033).
The Age to Join a 401(k)
An employer can require you to be at least 21 before letting you into its 401(k) plan.1U.S. Department of Labor. FAQs about Retirement Plans and ERISA That’s the federal maximum. Plenty of employers set a lower age or none at all, letting workers enroll at 18 or on their first day. But no plan can force you to wait past 21.
A plan can also require up to one year of service, defined as a 12-month period in which you work at least 1,000 hours.1U.S. Department of Labor. FAQs about Retirement Plans and ERISA For employer-funded contributions such as matching, that service requirement can be stretched to two years, but only if those contributions vest 100% immediately.2Internal Revenue Service. 401(k) Plan Qualification Requirements
Long-Term Part-Time Workers
Part-time employees used to be locked out if they never crossed 1,000 hours in a year. Under the SECURE Act and SECURE 2.0 rules now in effect, part-timers who work at least 500 hours in each of two consecutive 12-month periods and have reached age 21 must be allowed to make their own contributions. Employers can still exclude these workers from matching or profit-sharing contributions, and vesting schedules may differ, but the door to save is open.
Catch-Up Contributions Start at Age 50
The year you turn 50, you become eligible to contribute above the standard elective deferral limit. For 2026, the base cap is $24,500, and workers 50 and older can add another $8,000 in catch-up contributions, bringing the total to $32,500.3Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 You qualify as long as you turn 50 by December 31 of that year.4Internal Revenue Service. Issue Snapshot – 401(k) Plan Catch-Up Contribution Eligibility
There is no upper age limit. The IRS treats anyone “age 50 or over” as eligible.5Internal Revenue Service. Retirement Topics – Catch-Up Contributions Still working at 70? You can still make catch-ups.
The Enhanced Catch-Up Window: Ages 60 Through 63
SECURE 2.0 built in a larger catch-up for a narrow age band. If you’re 60, 61, 62, or 63 during the calendar year, your catch-up limit in 2026 rises to $11,250 instead of $8,000.3Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Combined with the $24,500 base, that lets participants in the window put away up to $35,750. The formula is the greater of $10,000 (indexed for inflation) or 150% of the standard catch-up. At 64, the limit drops back to the regular $8,000 catch-up rather than to zero.
Roth Catch-Ups for Higher Earners
Starting in 2026, catch-up contributions from higher-paid workers must go in as Roth. If your wages from the employer sponsoring the plan exceeded $145,000 in the prior calendar year (indexed for inflation), all of your catch-up dollars have to be after-tax rather than pre-tax.6Internal Revenue Service. Guidance on Section 603 of the SECURE 2.0 Act A transition period ran through the end of 2025, making 2026 the first year of full enforcement. If you were under the threshold in the prior year, you still choose pre-tax or Roth for your catch-up. Regular deferrals up to $24,500 stay pre-tax either way.
The Ages That Unlock Penalty-Free Withdrawals
The default rule: take money from a 401(k) before 59½ and you owe a 10% early withdrawal penalty on top of ordinary income tax.7Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions After 59½, the penalty is gone and only income tax applies. A handful of exceptions let you get to the money earlier.
The Rule of 55
Leave your job during or after the calendar year you turn 55, and you can take penalty-free distributions from that employer’s 401(k).7Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions The separation must happen in or after the year you hit 55. Quit at 54 and wait a year, and you don’t qualify. The exception covers only the plan tied to the job you left, not IRAs or 401(k)s from prior employers.
Age 50 for Public Safety Employees
The separation-from-service exception drops to age 50 for qualifying public safety workers. That covers state and local public safety employees in governmental plans, along with federal law enforcement officers, corrections officers, firefighters (including in the private sector), customs and border protection officers, and air traffic controllers.7Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions
Substantially Equal Periodic Payments
If you need access well before 55, the 72(t) exception lets you set up a series of substantially equal periodic payments (SEPP) at any age without the 10% penalty. You must have separated from the sponsoring employer, and once payments begin you cannot change the amount until the later of five years after they started or the year you reach 59½.8Internal Revenue Service. Substantially Equal Periodic Payments Modify the payments early and the IRS applies the 10% penalty retroactively to every distribution you already took.
Exceptions With No Age Requirement
Some penalty waivers aren’t tied to age at all. Unreimbursed medical expenses above 7.5% of adjusted gross income qualify, as does up to $5,000 per child following birth or adoption.7Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions SECURE 2.0 added exceptions for domestic abuse survivors (up to the lesser of $10,000 or 50% of the account) and emergency personal expenses (up to $1,000 per year). Income tax still applies to any of these distributions; only the 10% penalty is waived. If your Form 1099-R doesn’t carry the correct exception code, file Form 5329 to claim it.9Internal Revenue Service. 2025 Instructions for Form 5329
Roth 401(k) Age Rules Are Different
Roth 401(k) accounts (also called designated Roth accounts) share the same contribution and catch-up limits as traditional 401(k) accounts. The age rules diverge on the distribution side.
For a Roth 401(k) withdrawal to be fully tax-free including earnings, it has to be a qualified distribution. That requires two things: you must be at least 59½, and the account must have been open for at least five tax years, counted from January 1 of the year of your first contribution.10Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts Withdraw before meeting both, and your original contributions come out tax-free (you already paid tax on them) but the earnings portion is taxed as ordinary income and may be hit with the 10% penalty if you’re under 59½.
The other big shift: Roth 401(k) accounts no longer face required minimum distributions during the owner’s lifetime. SECURE 2.0 ended that requirement starting in 2024.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs The money can stay put as long as you live, which is a reason to start the five-year clock early even if you don’t expect to touch the account for decades.
Required Minimum Distributions Begin at Age 73
A traditional 401(k) can’t sit untouched forever. Once you reach the applicable age, the IRS requires annual withdrawals known as required minimum distributions. That age is currently 73.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Starting in 2033, it moves to 75.
Your first RMD is due by April 1 of the year after you reach RMD age. Every RMD after that is due by December 31.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Waiting until that April 1 for the first one means taking two RMDs in the same calendar year, which can push you into a higher bracket.
The Still-Working Exception
If you’re still employed by the company sponsoring your 401(k) and you don’t own more than 5% of the business, you can delay RMDs from that plan until April 1 of the year after you retire.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Only the current employer’s plan qualifies. Old 401(k) accounts and IRAs still follow the standard schedule.
Penalties for Missed RMDs
Missing the deadline triggers an excise tax of 25% on the shortfall.11Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Correct the mistake within two years and the penalty drops to 10%. Report the shortfall and pay the penalty on Form 5329.9Internal Revenue Service. 2025 Instructions for Form 5329 On a $20,000 missed RMD, the difference between 25% and 10% is $3,000.
Age Rules When Someone Inherits a 401(k)
Distribution rules for an inherited 401(k) depend on the beneficiary’s relationship to the original owner and, in some cases, the age gap between them.
Most non-spouse beneficiaries have to empty the account by the end of the tenth year following the owner’s death.12Internal Revenue Service. Retirement Topics – Beneficiary There’s no required annual withdrawal within that window. You can take it all in year one, spread it out, or wait until year ten, but the balance has to be gone by the deadline.
A smaller group, “eligible designated beneficiaries,” can stretch distributions over their own life expectancy instead:
- Surviving spouses can take distributions based on their own life expectancy or roll the account into their own 401(k) or IRA.
- Minor children can use life expectancy until reaching the age of majority, at which point the 10-year clock starts.
- Disabled or chronically ill individuals can use life expectancy at any age.
- Anyone not more than 10 years younger than the deceased owner can use life expectancy.12Internal Revenue Service. Retirement Topics – Beneficiary
The age-proximity rule catches people off guard. A 60-year-old inheriting from a 68-year-old sibling qualifies for life-expectancy distributions. A 50-year-old inheriting from the same person does not, because the gap exceeds 10 years. Eight years of difference in the beneficiary’s age changes the entire distribution timeline.