What is a 401(k) plan?

A 401(k) is an employer-sponsored retirement savings plan that lets you contribute a portion of your paycheck before taxes are taken out. The money grows tax-deferred inside the account - you pay no tax on investment gains year to year. When you withdraw in retirement, you pay ordinary income tax on the amount taken out. Many employers match a portion of your contributions, which is effectively free money added to your retirement savings.

What are the 401(k) contribution limits for 2025?

For 2025, the employee contribution limit for a 401(k) is $23,500. If you are age 50 or older, you can make an additional catch-up contribution of $7,500, bringing the total to $31,000. The overall limit including employer contributions is $70,000 (or $77,500 with catch-up). These limits are set by the IRS and typically increase each year with inflation.

What happens to my 401(k) if I leave my job?

When you leave a job, you have four main options for your 401(k): leave it with your former employer's plan (if allowed), roll it over into your new employer's 401(k) plan, roll it over into an IRA, or cash it out. Cashing out is almost always the worst option - you'll owe income tax on the full amount plus a 10% early withdrawal penalty if you're under 59.5. Rolling over to an IRA typically gives you the most investment options and control.

401(k) Explained: How It Works, Limits & Employer Match 2025

What Is a 401(k)?

A 401(k) is a retirement savings plan offered through your employer. The name comes from section 401(k) of the US tax code - it's not a catchy brand name, just a legal reference that stuck.

Here's how it works in plain terms: you choose a percentage of your paycheck to contribute, that money goes straight into your 401(k) before income taxes are calculated, and it gets invested in funds you select from your plan's options. The money grows tax-deferred - meaning you pay no tax on investment gains each year. You only pay income tax when you withdraw the money in retirement.

The big advantage is that your taxable income drops by the amount you contribute. If you earn $80,000 and contribute $10,000 to your 401(k), you only pay income tax on $70,000 that year. At a 22% marginal rate, that's $2,200 back in your pocket right now - plus the long-term compounding of the $10,000 inside the account.

If your employer offers a 401(k) match, contributing at least enough to get the full match is the single highest-return financial move available to you. A 50% match on up to 6% of salary is a guaranteed 50% return on that portion of your contribution before any investment growth occurs. No investment strategy can reliably beat free money.

2025 Contribution Limits

Contribution Type	2025 Limit	Who It Applies To
Employee contribution (under 50)	$23,500	All eligible employees
Catch-up contribution (age 50-59)	+$7,500	Workers aged 50-59
Super catch-up (age 60-63)	+$11,250	Workers aged 60-63 (new for 2025)
Total including employer contributions	$70,000	Combined employee + employer
Total with catch-up (50+)	$77,500	Workers 50+ with catch-up

Most people never come close to the maximum limit - and that's fine. Contributing consistently at a level you can maintain beats sporadic maximum contributions. The goal is to contribute enough to get the full employer match first, then increase contributions as your income grows.

The Employer Match - Don't Leave It Behind

An employer match is extra money your company adds to your 401(k) based on what you contribute. The most common structures are:

100% match on up to 3% of salary - contribute 3%, get 3% free
50% match on up to 6% of salary - contribute 6%, get 3% free
Dollar-for-dollar up to a fixed amount - e.g. $3,000/year maximum match

Not all employers offer a match - but if yours does, not contributing enough to get the full match is leaving part of your compensation on the table. It's worth thinking of the match as part of your salary, not a bonus.

Vesting schedules - your match may not be yours yet

Many employers use a vesting schedule - meaning you only fully own the employer match after working there for a certain number of years. A 3-year cliff vesting means you get 0% of the match if you leave before year 3, then 100% from year 3 onwards. A graded schedule might give you 20% per year. Check your plan documents so you know where you stand before considering a job change.

Traditional 401(k) vs Roth 401(k)

Many employers now offer both a Traditional and a Roth 401(k). The difference is when you get the tax break:

Tax now, save later

Traditional 401(k)

Contributions are pre-tax - they reduce your taxable income today. Money grows tax-deferred. You pay income tax when you withdraw in retirement. Better if you expect to be in a lower tax bracket in retirement than you are now.

Tax later, save now

Roth 401(k)

Contributions are after-tax - no upfront tax break. Money grows tax-free. Withdrawals in retirement are completely tax-free. Better if you expect to be in a higher tax bracket in retirement, or if you're early in your career with lower income now.

If you're unsure which to choose, many people split contributions between both - hedging against future tax rate uncertainty. Employer matches always go into the Traditional side regardless of which you choose for your own contributions.

What to Invest In Inside Your 401(k)

Most 401(k) plans offer a limited menu of funds chosen by your employer - typically 10-30 options. You won't have the full universe of investments available in an IRA. Common options include:

Target-date funds - e.g. "2055 Fund" - automatically adjust the mix of stocks and bonds as you approach retirement. The simplest one-decision option for most people
Index funds - low-cost funds tracking major indices like the S&P 500. Look for low expense ratios (under 0.10% is good, under 0.05% is excellent)
Actively managed funds - higher fees, rarely outperform index funds over long periods. Check the expense ratio before choosing
Company stock - some plans include your employer's own stock. Avoid concentrating too much here - you already rely on the company for your income

The expense ratio matters more than you think

A fund charging 1% per year vs one charging 0.05% per year sounds like a small difference. On $100,000 over 30 years at 7% growth, the 1% fund leaves you with around $574,000. The 0.05% fund leaves you with around $745,000. The difference is $171,000 - lost purely to fees. Always check expense ratios and favour the lowest-cost options that give you broad diversification.

Withdrawals and the Rules Around Them

A 401(k) is designed for retirement. Taking money out early has real consequences:

Normal withdrawals - available from age 59.5 onwards. You pay ordinary income tax on the amount withdrawn
Required Minimum Distributions (RMDs) - from age 73, you must take a minimum withdrawal each year whether you want to or not. Roth 401(k)s are now exempt from RMDs during the account holder's lifetime (from 2024)
Early withdrawal (before 59.5) - you pay income tax plus a 10% penalty on the amount taken out

Early withdrawal is expensive - do the maths first

Taking $20,000 from a 401(k) at age 40 (assuming 22% tax bracket) costs $6,400 in income tax plus $2,000 in penalty = $8,400 lost immediately. Plus you lose the future compounding of that $20,000 over 20+ years. In most situations, a personal loan, home equity line, or cutting expenses is cheaper than an early 401(k) withdrawal. Hardship withdrawals and loans against your 401(k) balance are available in some circumstances - both have their own rules and costs.

Leaving Your Job - What Happens to Your 401(k)?

When you leave an employer, you have four choices for your 401(k):

Leave it with your former employer - allowed in most plans if your balance is over $5,000. Simple but you may have limited investment options and less visibility
Roll it into your new employer's 401(k) - keeps everything in one place. Only possible if the new plan accepts incoming rollovers
Roll it into an IRA - typically the best option for investment choice and control. No tax consequences if done as a direct rollover
Cash it out - worst option in nearly all cases. Triggers income tax plus 10% penalty if under 59.5. Only consider this in a genuine financial emergency with no other options

Frequently Asked Questions

For 2025, the employee contribution limit is $23,500. Workers aged 50-59 can add a $7,500 catch-up contribution (total $31,000). Workers aged 60-63 can add $11,250 under a new super catch-up provision introduced in 2025 (total $34,750). The combined employee plus employer limit is $70,000, or $77,500 with standard catch-up contributions.

You have four options: leave it with your former employer (if the balance is over $5,000 and the plan allows), roll it into your new employer's plan, roll it into an IRA, or cash it out. Rolling into an IRA gives you the most investment options and control. Cashing out triggers income tax plus a 10% penalty if you're under 59.5 - avoid this unless you have no other options.

If you're early in your career with lower income now and expect higher income later, Roth makes sense - you pay tax now at a lower rate and withdrawals are tax-free later. If you're in your peak earning years and want to reduce taxable income now, Traditional is often better. If you're unsure, splitting contributions between both hedges against future tax rate changes. Employer matches always go into the Traditional side regardless of your choice.

You can, but it's costly. Withdrawals before age 59.5 trigger income tax on the full amount plus a 10% early withdrawal penalty. Some exceptions exist - certain hardships, disability, substantially equal periodic payments (SEPP), and separation from service at age 55 or older. Many plans also allow loans of up to 50% of your vested balance (max $50,000), which you repay with interest back to yourself. A loan avoids the penalty but has risks if you leave the job before repaying it.

Important: 401(k) rules, limits, and tax treatment are set by the IRS and can change. Always verify current limits at irs.gov or with your plan administrator. This is educational content only - not financial or tax advice. Consider speaking with a qualified financial adviser or tax professional for personal guidance.