What Is a 401(k)? How It Works, in Plain English
Takeaways
- A 401(k) is a retirement savings plan offered through your employer that lets you invest part of each paycheck.
- Contributions may be made pre-tax (traditional) or after-tax (Roth), depending on what your plan offers.
- Many employers add matching contributions, which may be one of the most valuable parts of the plan.
- For 2026, you can contribute up to $24,500, plus catch-up contributions if you’re 50 or older.
- Enrolling is only the first step. How your account is invested, and how often you review it, can matter just as much.
What Is a 401(k)?
A 401(k) is a retirement savings plan sponsored by an employer.
It gets its name from Section 401(k) of the Internal Revenue Code, the part of the tax law that created it.
Here’s a simple version: you choose a percentage of your paycheck to set aside. That money goes into your 401(k) account before it ever hits your bank account. It’s then invested in a menu of funds your plan offers.
Over time, the goal is for those contributions, and any growth on them, to help fund your retirement.
For tens of millions of Americans, a 401(k) is the primary way they save for retirement.
But being enrolled and understanding how your 401(k) works are two different things.
How Does a 401(k) Work?
Most 401(k)s follow the same basic steps:
- You enroll. Many employers now enroll new hires automatically at a default contribution rate. You can usually change that rate.
- You choose how much to contribute. This is typically a percentage of each paycheck.
- Your employer may contribute, too. Many companies match part of what you put in.
- You choose your investments. Your plan offers a list of funds, often including target-date funds, stock funds, bond funds and a stable value or money market option. If you don’t choose, your money usually goes into a default investment.
- Your account grows or shrinks with the markets. Your balance changes as the value of your investments changes.
- You withdraw in retirement. Once you reach retirement age, you can begin taking distributions.
The steps are simple. The decisions inside each step are where it can get complicated.
Traditional vs. Roth 401(k): What’s the Difference?
Many plans now offer two ways to contribute.
Traditional 401(k) contributions are made before income taxes are taken out. That may lower your taxable income today. You generally pay ordinary income tax on the money when you withdraw it in retirement.
Roth 401(k) contributions are made after taxes. You don’t get a tax break today. But qualified withdrawals in retirement, including the growth, may be tax-free.
Which is better? It depends on your income today, what you expect your tax bracket to be in retirement, and your overall plan. Some savers split contributions between both.
We believe this is a decision worth talking through with a tax professional.
What Is a 401(k) Employer Match?
An employer match is money your company adds to your account based on what you contribute.
For example, a plan might match 50% of your contributions up to 6% of your pay. If you contribute 6%, your employer adds another 3%.
If you contribute less than the amount needed to get the full match, you may be leaving part of your total compensation on the table.
Not every employer offers a match, and match formulas vary. Your plan’s Summary Plan Description will spell out the details.
What Does “Vested” Mean in a 401(k)?
Vesting determines how much of your account you own if you leave your job.
The money you contribute from your paycheck is always 100% yours, according to the IRS.
Employer contributions may follow a vesting schedule. For example, under a three-year “cliff” schedule, you own none of the match until you reach three years of service, then you own all of it. Under a “graded” schedule, you own a larger percentage each year.
If you’re thinking about changing jobs, it may be worth checking your vesting status first. Learn more about 401(k) vesting schedules.
How Much Can You Contribute to a 401(k) in 2026?
The IRS sets limits each year. For 2026:
| Contribution type | 2026 limit |
|---|---|
| Employee contributions (under 50) | $24,500 |
| Catch-up contributions (age 50+) | Additional $8,000 |
| “Super” catch-up (ages 60–63) | Additional $11,250 (instead of $8,000) |
Employer contributions don’t count toward your $24,500 limit. They fall under a separate, higher combined limit.
What Are the Tax Advantages of a 401(k)?
The tax treatment is one of the main reasons 401(k)s are popular.
- Traditional contributions may reduce your taxable income in the year you make them.
- Investment growth isn’t taxed while it stays in the account, so you don’t owe taxes when your investments earn dividends or when you move money between funds.
- Roth contributions may offer tax-free qualified withdrawals in retirement.
Those advantages come with rules about when you can take the money out.
When Can You Withdraw From a 401(k)?
401(k)s are designed for retirement, so early access is limited.
In general, if you withdraw money before age 59½, you may owe a 10% additional tax on top of regular income tax, unless an exception applies. One common exception: if you leave your job during or after the year you turn 55, you may be able to take withdrawals from that employer’s plan without the 10% additional tax.
On the other end, required minimum distributions (RMDs) from traditional 401(k) balances generally begin the year you reach age 73. Roth 401(k) balances aren’t subject to RMDs while the owner is alive.
Some plans also allow loans or hardship withdrawals. Each has trade-offs that may affect your long-term savings. Here’s how you can avoid 401(k) withdrawal penalties.
What Happens After You Enroll?
This is where many savers stop paying attention.
They enroll, pick a contribution rate, maybe pick a fund, and then don’t look again for years.
But a 401(k) isn’t “set it and forget it” by default. A few things we recommend you check at least once a year:
- Your contribution rate. Are you getting the full employer match? Could you increase it after a raise?
- Your investment mix. Does it still match your risk tolerance and how far you are from retirement? Markets can shift your allocation even if you never make a change. Here’s why that matters.
- Your fees. Fund expense ratios and plan fees can reduce your account’s growth over time.
- Your statement. It shows your balance, contributions, vesting and returns in one place. Here’s how to read a 401(k) statement.
Should You Get Help Managing Your 401(k)?
You can manage your 401(k) on your own.
But if you’re not sure how your account is invested, whether your mix fits your goals, or when to make changes, professional guidance may help.
401(k) Maneuver provides independent, professional account management for the 401(k) you already have through work. Your account stays with your current plan provider.
Here’s what you can expect as a 401(k) Maneuver client:
- Professional quarterly 401(k) account rebalancing, personalized to your tolerance for risk and based on current economic and market conditions.
- An email notification every time we review your account.
- Membership in our online community, with content to help you prepare for retirement.
- Access to a private Facebook group where you can ask our advisors questions.
