Everything You Need to Know About Your Workplace Retirement Plan

A 401(k) is a workplace retirement plan that lets you invest part of every paycheck for retirement, with tax advantages that help your money grow faster. You choose a percentage of your salary to contribute, your employer may add matching money on top, and the account is invested in funds you select from the plan’s menu.

With a traditional 401(k), contributions come out of your pay before income tax, lowering your tax bill today, and you pay tax when you withdraw in retirement. With a Roth 401(k), you contribute after-tax money now, and qualified withdrawals in retirement, including all the growth, are tax-free.

For millions of Americans, the 401(k) is the single most important wealth-building tool they have. This guide explains how it works from enrollment to retirement: contribution limits, employer matching, vesting, investment choices, fees, withdrawals, loans, rollovers and required distributions, with worked examples throughout.

Start Here: Learn With FRC

Financial Regulation Courses (FRC) has no stake in your retirement plan. FRC sells no investments, manages no money and earns no commission, so this guide is built on how the rules actually work.

For a video walkthrough of retirement accounts and investing basics, the FRC Retail Investing video series covers these topics step by step. Most 401(k) plans now invest heavily through index funds and ETF-style portfolios, and FRC’s ETF Investing for Beginners course explains how those funds work, followed by ETF Investing Strategies.

FRC’s programs and memberships are open to everyone. If you are completely new to investing, start with FRC’s Investing for Beginners guide, then come back here.

Where the 401(k) Came From

The 401(k) takes its name from section 401(k) of the Internal Revenue Code, added by the Revenue Act of 1978. The provision allowed employees to defer part of their pay into a retirement plan without paying income tax on it immediately.

Benefits consultant Ted Benna is widely credited with designing the first 401(k) savings plan around 1980, after realizing the new rule could be used to let employees save their own salary with an employer match. Within a few years, employers across the country had adopted the idea.

Over the following decades, the 401(k) largely replaced the traditional pension for private-sector workers. Responsibility for retirement shifted from the employer to the employee, which is why understanding your 401(k) has become so valuable.

How a 401(k) Works Step by Step

When you join your employer’s plan, you choose what percentage of each paycheck to contribute. That money is taken out of your pay automatically through payroll and deposited into your 401(k) account.

Inside the account, you pick investments from a menu chosen by your employer, typically a mix of stock funds, bond funds, target-date funds and a stable value or money market option. Your money then grows tax-deferred, meaning you pay no tax on dividends, interest or gains while it stays in the plan.

When you retire, you withdraw money to live on. At that point, withdrawals from a traditional 401(k) are taxed as ordinary income, while qualified withdrawals from a Roth 401(k) are tax-free.

Traditional 401(k) vs Roth 401(k)

A traditional 401(k) gives you the tax break now. Every dollar you contribute reduces your taxable income for the year, so a worker in the 22% federal bracket who contributes $10,000 saves about $2,200 in federal income tax.

A Roth 401(k) gives you the tax break later. Contributions are made with money that has already been taxed, but qualified withdrawals after age 59½, once the account has been open at least five years, are completely tax-free, including decades of growth.

The choice often comes down to whether you expect your tax rate to be higher now or in retirement. Younger workers in lower brackets often favor the Roth, while higher earners at their peak often favor the traditional option, and many plans let you split contributions between the two.

401(k) Contribution Limits

The IRS sets a limit each year on how much employees can contribute. For 2026, the employee contribution limit is $24,500, covering traditional and Roth contributions combined.

Workers aged 50 and over can add a catch-up contribution of $8,000 for 2026, for a total of $32,500. Under the SECURE 2.0 Act, workers aged 60 to 63 qualify for a higher catch-up of $11,250 in place of the standard catch-up.

The IRS publishes the following year’s limits each fall. Benefits consultants widely project the 2027 employee limit will rise to $25,500, with the IRS expected to confirm the official figures in November 2026.

The Total Annual Limit

Separate from the employee limit, there is an overall cap on all contributions to your account in a year, including employer matches and profit-sharing. For 2026, this total limit is $72,000, not counting catch-up contributions.

Most workers never come close to the total limit. It becomes relevant for high earners with generous employer contributions, or for people who make after-tax contributions in plans that allow them. Self-employed people using a solo 401(k) also need to track it, because they contribute as both employee and employer.

Plans that accept after-tax contributions and allow in-plan conversions make a strategy known as the mega backdoor Roth possible. It lets high savers move far more money into Roth accounts than the standard limits would allow.

The New Roth Catch-Up Rule

SECURE 2.0 also changed how catch-up contributions work for higher earners. Starting in 2026, workers aged 50 and over whose wages from the employer exceeded an inflation-adjusted threshold in the prior year, $150,000 for 2025 wages, must make their catch-up contributions as Roth contributions.

This means those workers lose the immediate tax deduction on the catch-up portion. In exchange, that money and its growth can come out tax-free in retirement.

Workers below the threshold can still choose between traditional and Roth catch-up contributions. If your plan does not offer a Roth option, it may not allow catch-up contributions for affected high earners at all.

Employer Matching: Free Money

Many employers match part of what you contribute. A common formula is 50 cents for every dollar you contribute, up to 6% of your salary, and another is a dollar-for-dollar match on the first 3% plus 50 cents on the next 2%.

Consider a worker earning $60,000 whose employer matches 50% of contributions up to 6% of pay. If the worker contributes 6%, or $3,600 a year, the employer adds $1,800, an instant 50% return before any investment growth.

Contributing less than the amount needed for the full match leaves free money on the table. For most workers, capturing the full match is the first priority before any other investing, as FRC’s guide to the order to invest across a 401(k), IRA or brokerage account explains.

Vesting: When the Match Becomes Yours

Your own contributions are always 100% yours from the moment they are made. Employer contributions, however, may be subject to a vesting schedule, which sets how long you must work there before that money is fully yours.

Under federal rules, a cliff vesting schedule can require up to three years of service, after which you become 100% vested at once. A graded schedule can phase in ownership over up to six years, such as 20% after two years rising to 100% after six.

If you leave before you are fully vested, you forfeit the unvested portion of the employer’s contributions. Checking your plan’s vesting schedule before changing jobs can be worth thousands of dollars.

Automatic Enrollment

Many employers enroll new workers in the 401(k) automatically, starting contributions at a default percentage unless the employee opts out. Under SECURE 2.0, most new 401(k) plans established after December 29, 2022 must automatically enroll eligible employees starting in 2025.

These plans must start contributions at between 3% and 10% of pay and increase the rate by one percentage point a year until it reaches at least 10%, up to a maximum of 15%. Existing plans, small businesses and new companies are exempt.

Automatic enrollment is a powerful nudge. If you have been auto-enrolled, check your contribution rate and your investment choice, because the default may be lower than you need to receive the full employer match, and the default fund may not suit your timeline.

What You Can Invest in Inside a 401(k)

Your employer, as plan sponsor, chooses the investment menu. Typical options include US and international stock funds, bond funds, a stable value or money market fund, and a series of target-date funds.

Many plans now offer low-cost index funds that track the S&P 500 or the total stock market. FRC’s guide to how to invest in the S&P 500 explains what these funds hold, and FRC’s guide to Fidelity index funds shows how one of the largest 401(k) providers structures its index options.

Your mix of stock and bond funds is your asset allocation. It has a larger effect on your long-term results than any single fund choice.

Target-Date Funds: The Default Choice

A target-date fund holds a diversified mix of stocks and bonds based on the year you expect to retire, such as a 2060 fund for someone retiring around 2060. As that date approaches, the fund gradually shifts from stocks towards bonds, a process known as the glide path.

Target-date funds are the most common default investment in 401(k) plans. Federal rules recognize them as a qualified default investment alternative, the option a plan can use when an employee does not choose investments.

They suit investors who want a single, hands-off choice. The main things to check are the fund’s expense ratio and whether its stock-to-bond mix matches your own comfort with risk.

Fees in Your 401(k)

Every fund in your plan charges an expense ratio, and some plans add administrative or recordkeeping fees. These costs come out of your returns every year.

Small differences add up over a career. On a $100,000 balance, a fund charging 0.05% costs $50 a year, while one charging 1% costs $1,000, and that gap compounds over decades.

Your plan must give you a fee disclosure explaining these costs. When your plan offers a low-cost index fund alongside more expensive actively managed funds, the cost difference deserves careful thought.

Who Protects Your 401(k)?

Most private-sector 401(k) plans are governed by the Employee Retirement Income Security Act of 1974, known as ERISA. ERISA requires the people running the plan to act as fiduciaries, managing it prudently and solely in the interest of participants.

The plan’s assets are held in trust, separate from your employer’s own business assets. If your employer goes bankrupt, its creditors cannot claim the money in your 401(k).

Plans must also file an annual report, Form 5500, with the government and give participants regular statements and disclosures. The Department of Labor oversees ERISA compliance, while the IRS enforces the tax rules.

The Power of Starting Early

The tax-deferred growth inside a 401(k) makes compound interest especially powerful, because no tax is taken out of the returns each year. Every dollar of growth stays invested and earns further returns.

Consider two workers who each contribute $500 a month and earn an average return of 7% a year. The one who starts at 25 and contributes until 65 ends up with roughly $1.3 million, while the one who starts at 35 ends up with roughly $600,000, less than half, despite contributing for only 10 fewer years.

FRC’s guides to how compound interest builds wealth and how much $500 a month grows over 30 years show the math in more detail. The lesson is simple: the earlier you start, the less you need to contribute to reach the same goal.

How Much Should You Contribute?

At a minimum, contribute enough to receive the full employer match. Beyond that, many retirement planners suggest saving around 15% of pay for retirement in total, including the employer’s contribution.

If 15% feels out of reach, start where you can and increase gradually. Raising your contribution by one percentage point each year, or every time you get a raise, builds savings without a noticeable drop in take-home pay.

Contributing through every paycheck is a form of dollar-cost averaging. You buy more shares when prices are low and fewer when they are high, without having to time the market.

Withdrawing Money Before Retirement

A 401(k) is designed for retirement, and early withdrawals are discouraged. Withdrawals from a traditional 401(k) before age 59½ are generally taxed as ordinary income and also face a 10% early withdrawal penalty.

There are exceptions to the penalty. They include the rule of 55, which allows penalty-free withdrawals from your current employer’s plan if you leave that job in or after the year you turn 55, as well as disability, certain medical expenses and payments under a court order in a divorce.

SECURE 2.0 added further options, including one emergency withdrawal of up to $1,000 a year for personal or family emergency expenses. Plans may also allow hardship withdrawals for immediate and heavy financial needs, though income tax still applies.

401(k) Loans

Many plans let you borrow from your own 401(k). You can generally borrow up to the lesser of $50,000 or 50% of your vested balance, and most loans must be repaid within five years through payroll deductions.

You pay interest on the loan, but the interest goes back into your own account. The real cost is the growth you miss while the money is out of the market.

The biggest risk comes if you leave your job. Many plans require the outstanding balance to be repaid by your tax filing deadline for that year, and any unpaid amount is treated as a withdrawal, subject to income tax and possibly the 10% penalty.

What Happens When You Change Jobs

When you leave an employer, you have several choices for your 401(k). You can usually leave it in the old plan, roll it into your new employer’s plan, roll it into an individual retirement account, or cash it out.

Cashing out is usually the costliest choice, because the money is taxed as income and may face the 10% penalty. A direct rollover, where the money moves straight from one plan or provider to another, avoids tax and penalties completely.

If the plan sends the money to you instead, it must withhold 20% for taxes, and you have 60 days to deposit the full amount into an IRA or new plan to avoid tax. Rolling into an IRA gives you a wider choice of investments, while staying in a 401(k) can offer stronger creditor protection and access to the rule of 55.

401(k) vs IRA

A 401(k) and an IRA are both tax-advantaged retirement accounts, but they differ in important ways. A 401(k) is offered through your employer, has much higher contribution limits and may include a match, while an IRA is opened by you, has a lower limit and offers a wider range of investments.

For 2026, the IRA contribution limit is $7,500, plus a $1,100 catch-up for those aged 50 and over. Roth IRA contributions phase out for single filers with modified adjusted gross income between $153,000 and $168,000, and for married couples filing jointly between $242,000 and $252,000.

Many investors use both: first the 401(k) up to the match, then an IRA, then more 401(k) contributions. Higher earners above the Roth IRA limits can use the strategy in FRC’s guide to the backdoor Roth IRA.

Roth 401(k) vs Roth IRA

Both accounts offer tax-free qualified withdrawals, but they work differently. A Roth 401(k) has no income limit for contributions, so high earners who cannot contribute directly to a Roth IRA can still save Roth money through their workplace plan.

A Roth 401(k) also has the much higher 401(k) contribution limit, while a Roth IRA offers a wider range of investments and more flexible access to contributions. Roth IRA contributions, though not earnings, can be withdrawn at any time without tax or penalty.

When you leave an employer, a Roth 401(k) can be rolled into a Roth IRA. Since 2024, neither account requires minimum distributions during the owner’s lifetime, which removes one of the old differences between them.

The Saver’s Match Arrives in 2027

Lower- and moderate-income workers have long been able to claim the Saver’s Credit, a tax credit for contributing to a retirement account. Starting with the 2027 tax year, SECURE 2.0 replaces it with the Saver’s Match.

Instead of a credit on your tax return, the federal government will deposit a matching contribution directly into your eligible retirement account. The match is worth up to 50% of the first $2,000 you contribute each year, for a maximum of $1,000 per person, phasing out as income rises.

For eligible savers, this is another source of free money on top of any employer match. It makes contributing to a 401(k) or IRA even more valuable for workers on modest incomes.

Required Minimum Distributions

The government eventually wants its tax on traditional 401(k) money. Under SECURE 2.0, you must generally begin taking required minimum distributions from traditional 401(k)s at age 73, rising to 75 for people who turn 74 after December 31, 2032.

The amount is calculated each year from your account balance and an IRS life expectancy table. Missing a required distribution can trigger a penalty of 25% of the amount not taken, reduced to 10% if corrected promptly.

Since 2024, Roth 401(k) accounts are no longer subject to required minimum distributions during the owner’s lifetime. If you are still working at the required age and do not own 5% or more of the company, your current employer’s plan may let you delay distributions until you retire.

401(k) Options for the Self-Employed

Self-employed people without employees can open a solo 401(k), also called an individual 401(k). It lets the owner contribute both as the employee, up to the employee limit, and as the employer, through profit-sharing contributions, subject to the total annual limit.

This often allows far larger contributions than an IRA. A self-employed consultant with strong income can shelter a substantial share of earnings each year.

Alternatives include the Simplified Employee Pension, or SEP IRA, which is simpler to set up but allows employer contributions only. The right choice depends on income level and whether the business has employees.

Is Your 401(k) Money Safe?

Your 401(k) is held in trust and protected from your employer’s creditors under ERISA. The investments themselves, however, can rise and fall with the markets.

The assets are usually held by a large recordkeeper or custodian, such as Fidelity, Vanguard, Empower or Charles Schwab. FRC’s guide to whether your money is safe in a brokerage account explains how custody and investor protection work.

The bigger risk for most savers is behavior, not fraud. Cashing out when changing jobs, borrowing heavily or selling in a panic during market falls can do far more damage than any market decline.

Common 401(k) Mistakes

The first mistake is not contributing enough to receive the full match. It is one of the few guaranteed returns in investing.

The second is leaving money in cash or a low-return option for years, often because an auto-enrolled worker never chose investments. Cash held for decades loses ground to inflation.

The third is cashing out old 401(k)s when changing jobs, and the fourth is ignoring fees. Each of these can quietly cost a worker tens of thousands of dollars by retirement.

A Simple 401(k) Checklist

Enroll as soon as you are eligible and contribute at least enough to receive the full employer match. Decide between traditional and Roth contributions based on your tax bracket now and the bracket you expect in retirement.

Choose a diversified, low-cost investment, such as a target-date fund or a mix of broad index funds, and check that it matches your comfort with risk. Raise your contribution by at least one percentage point each year until you reach your savings goal.

Review your account once or twice a year, check your vesting schedule before changing jobs, and roll old plans directly into your new plan or an IRA rather than cashing out. Keep your beneficiary designations up to date.

Keep Learning

A 401(k) rewards people who understand it. The more you know about how its funds work, how it is taxed and what the rules allow, the more of its benefits you capture.

The FRC dictionary is more than a dictionary. It is a library of explainer videos, written explanations and on-page quizzes, so you can open any term, such as retirement planning, and go deeper whenever something is unclear.

FRC’s programs and memberships are open to everyone, from first-time savers to people building careers in finance. Structured learning turns a confusing benefits package into a plan you control.

Your Next Step

A 401(k) lets you invest part of every paycheck with valuable tax advantages, often boosted by free employer money. Capture the full match, choose low-cost diversified funds, increase your contributions over time and avoid cashing out, and the account can grow into the foundation of your retirement.

Log in to your plan today, check your contribution rate and your investments, and make sure your money is working as hard as you are.