What Is a 401(k)?
If you've started working a full-time job, you've probably seen something about a "401(k)" in your benefits paperwork. The name comes from a section of the US tax code — not exactly inspiring — but the account itself is one of the most powerful wealth-building tools available to ordinary workers.
A 401(k) is a retirement savings account offered through your employer. Money goes in directly from your paycheck, either before taxes (Traditional) or after taxes (Roth). The money grows inside the account without being taxed each year. You typically can't withdraw it without a penalty until age 59½, which is the point — it's specifically designed for retirement savings.
But the real reason a 401(k) matters isn't the tax treatment. It's the employer match.
The Employer Match: Actual Free Money
An employer match is money your company adds to your 401(k) on top of your own contributions — at no cost to you. Common formulas include "50% match up to 6% of salary" or "dollar-for-dollar up to 3%." If you don't contribute enough to get the full match, you're leaving part of your compensation uncollected. There's no investment in the world that gives you a guaranteed 50–100% instant return on your money.
Different employers use different match formulas. Here are the most common ones:
- 50% match up to 6%: For every dollar you contribute (up to 6% of your salary), the employer adds 50 cents. If you contribute 6%, the employer adds 3%.
- Dollar-for-dollar up to 3%: The employer matches your contribution 100%, but only on the first 3% of salary.
- Dollar-for-dollar up to 4%: Same idea, but with a slightly higher cap.
- Flat contribution: Some employers contribute a fixed percentage (say, 3%) regardless of what you put in.
The formula doesn't matter as much as this: you need to know what your match is and contribute at least enough to capture every dollar of it.
Alex earns $60,000 per year. The employer matches 50% of contributions up to 6% of salary. If Alex contributes 6% ($3,600/year), the employer adds 3% ($1,800/year). That's $1,800 in extra compensation per year for doing nothing except signing up and choosing a contribution rate. Over a 30-year career — without even counting investment growth — that match alone would be $54,000 in employer money.
If Alex only contributes 3%, the employer adds 1.5% ($900). Alex is capturing only half the match and leaving $900/year on the table. At 4%, the employer adds 2% ($1,200) — better, but still missing $600. Only at 6% does Alex get the full $1,800.
Sam earns $50,000 and the employer matches 100% of contributions up to 3%. Sam contributes 3% ($1,500/year) and gets another $1,500 from the employer — doubling the money instantly. Contributing 4% or 5% won't increase the match; the employer stops matching at 3%. But Sam is still getting a 100% return on those first 3% of contributions. No stock, bond, or savings account will ever match that.
The misconception: When money is tight, the 401(k) contribution feels like a luxury you can't afford.
The reality: Not contributing enough to get the full employer match means you're declining part of your pay. If your employer offers a 50% match on 6%, contributing 6% of a $50,000 salary costs you about $115 per biweekly paycheck after the tax savings (less for Traditional, since contributions reduce taxable income). In return, you get $1,500/year from your employer. That's a 50% return with zero risk. Even if you have to cut back elsewhere temporarily, the match is almost always worth getting. You can increase other savings later — but you can never go back and recapture missed match years.
Contribution Limits
The Internal Revenue Service (IRS) sets annual limits on how much you can put into a 401(k). For 2026:
- Under age 50: $23,500 per year (your contributions only — employer match doesn't count against this limit)
- Age 50 or older: $31,000 per year (the extra $7,500 is called a "catch-up contribution")
These limits tend to increase every year or two to keep up with inflation. Most people don't hit the limit — the median 401(k) contribution is well below it. The limit matters more as your income grows and you start maxing out the account.
One important detail: the employer match does not count toward your contribution limit. If you contribute $23,500 and your employer adds $5,000 in match, the total going into the account is $28,500, and that's perfectly fine.
Traditional 401(k) vs. Roth 401(k): A Quick Look
Most employers now offer two flavors of 401(k):
- Traditional 401(k): Contributions reduce your taxable income now. You pay income taxes when you withdraw the money in retirement.
- Roth 401(k): Contributions come from after-tax dollars (no tax break now). Withdrawals in retirement are completely tax-free.
The decision between them depends on whether you expect to be in a higher or lower tax bracket in retirement compared to today. Early in your career, when your income is likely at its lowest, the Roth option often makes sense — you're paying taxes at today's low rate and locking in tax-free withdrawals later. But this is a bigger topic, and the next article dives deep into it.
Whichever type you choose, the employer match is always deposited as Traditional (pre-tax) money, even if your own contributions are Roth. This is a tax code rule, not a choice.
Vesting: Your Money vs. Their Money
A vesting schedule determines when you fully own the employer match money in your 401(k). Your own contributions are always 100% yours — you can take them with you if you leave the company. But employer match contributions may vest over time. Common schedules: cliff vesting (0% until a specific year, then 100% — e.g., fully vested after 3 years) or graded vesting (gradual increase — e.g., 20% per year over 5 years). If you leave before being fully vested, you forfeit the unvested employer portion.
Maya has been at her company for 2 years and 8 months. Her employer uses a 3-year cliff vesting schedule. She has $9,000 in employer match contributions. Maya gets an offer from another company — better role, $5,000 more per year. If she leaves now, she loses all $9,000 in unvested match. If she waits 4 months, she keeps every dollar.
This doesn't mean Maya should always wait — the new opportunity might be worth far more than $9,000 over time. But she should factor the vesting timeline into the decision. It's real money that disappears if she doesn't account for it.
What to Invest In (Inside Your 401(k))
Money in your 401(k) isn't automatically invested — you have to choose what it goes into. Most plans offer a menu of mutual funds: stock funds, bond funds, target-date funds, and sometimes a stable value or money market fund.
If you're early in your career and don't know much about investing yet, a target-date fund is a reasonable default. These funds automatically adjust their mix of stocks and bonds based on when you plan to retire. You pick the fund with the year closest to your expected retirement (e.g., a "2060 fund" if you expect to retire around 2060), and it does the rest. It's not the only option, but it's a sensible starting point that keeps you invested rather than paralyzed by choices.
The one thing to watch: expense ratios. Every fund charges a fee, expressed as a percentage of your balance per year. A 0.05% fee on $100,000 costs $50/year. A 1.0% fee on that same balance costs $1,000/year. Over 30 years, that difference compounds enormously. Look at the fees on the funds your plan offers. If you see options under 0.10%, those are typically index funds — and they're usually the best value.
Common 401(k) Mistakes
The biggest 401(k) mistakes are surprisingly basic — and they cost people tens or hundreds of thousands of dollars over a career:
- Not enrolling at all. Some employers auto-enroll new employees; many don't. If you don't actively sign up, you get nothing — no contributions, no match, no growth. Check your enrollment status in your first week.
- Not contributing enough for the full match. Contributing 2% when your employer matches up to 6% means you're capturing only a fraction of the free money. Always hit the match threshold at minimum.
- Leaving money in cash or stable value. Some 401(k) plans default your contributions to a money market or stable value fund — essentially cash. That earns 1–3% and barely keeps up with inflation. If you're decades from retirement, that money should be invested in stocks, not parked in cash.
- Ignoring fees. Some 401(k) plans include funds with expense ratios above 1%. Over 30 years, a 1% fee versus a 0.05% fee on $500/month contributions can cost you over $100,000 in lost growth. Check the fee on every fund you choose.
- Cashing out when you leave a job. If you leave an employer and cash out your 401(k) instead of rolling it over to an Individual Retirement Account (IRA) or your new employer's plan, you owe income taxes on the full amount plus a 10% early withdrawal penalty if you're under 59½. A $30,000 cash-out could net you only $19,000–$21,000 after taxes and penalties.
Open the 401(k) Calculator and try this:
- Enter your salary (or use $60,000 as an example), set your contribution to 6%, employer match to 50% up to 6%, and years to retirement to 30.
- Note the final balance and how much came from the employer match versus your own contributions.
- Now change your contribution to 3% and see how much smaller the match portion becomes.
- Try setting the contribution to 0% — this is what not enrolling costs you over a career.
The difference between "not enrolled" and "enrolled at the match threshold" is often hundreds of thousands of dollars — most of it from employer money and investment growth, not your own paycheck.
- A 401(k) is an employer-sponsored retirement account with tax advantages. Traditional contributions are pre-tax; Roth contributions are after-tax with tax-free withdrawals in retirement.
- The employer match is part of your compensation. Not contributing enough to get the full match is leaving money on the table — the equivalent of declining part of your salary.
- For 2026, the contribution limit is $23,500 under age 50 ($31,000 with catch-up contributions for age 50+). Employer match doesn't count against your limit.
- Vesting schedules determine when you own the employer match. Know your schedule before making job-change decisions.
- If you're unsure what to invest in, a target-date fund is a reasonable starting point. Whatever you choose, check the expense ratio — low-fee index funds save you thousands over time.
- Enroll immediately, hit the match threshold, don't leave money in cash, and never cash out when switching jobs — roll it over instead.