401(k) Basics: How It Works, 2026 Limits and the Employer Match

For most working Americans, the 401(k) is the single most powerful retirement tool they have. Contributions come straight out of your paycheck, grow without yearly taxes, and often come with free money from your employer. Here is how it works and how to get the most out of it in 2026.

What is a 401(k)?

A 401(k) is an employer-sponsored retirement plan, named after a section of the tax code. You choose a percentage of each paycheck to contribute, pick investments from the plan's menu, and the money grows tax-advantaged until retirement. Government and nonprofit employers offer similar plans called 403(b)s and 457(b)s.

Most plans offer two flavors:

• Traditional (pre-tax) 401(k): contributions reduce your taxable income now; withdrawals in retirement are taxed.
• Roth 401(k): contributions are made after tax; qualified withdrawals in retirement are tax-free.

The trade-off is the same one we explain in Roth IRA vs traditional IRA: pay tax when your rate is lower.

2026 401(k) contribution limits

The employee limit covers your traditional and Roth 401(k) contributions combined. Employer contributions are on top of it, under a separate, higher overall limit.

The employer match: don't leave it on the table

Many employers match part of what you contribute. A common formula is 50% of your contributions up to 6% of your salary.

Example: you earn $60,000 and contribute 6% ($3,600 a year). Your employer adds 50% of that, $1,800. That's an instant 50% return before any investment growth. If you only contributed 3%, you would get just $900 of the match.

That is why the usual first rule of retirement saving is: contribute at least enough to get the full match, even while you are paying off debt or building an emergency fund.

Vesting: when the match is really yours

Your own contributions are always 100% yours. Employer contributions may follow a vesting schedule, for example 20% per year of service until fully vested after a set number of years. If you leave before you are vested, you can lose the unvested part. Check your plan's summary plan description before changing jobs.

What to invest in

Your 401(k) is only as good as the investments inside it. Common choices:

• Target-date funds: pick the fund with the year closest to your retirement (for example, a "2060 fund"). It automatically shifts from stocks toward bonds as that year approaches. It is a simple, hands-off option.
• Index funds: low-cost funds that track a market index like the S&P 500 or the total U.S. market. See index funds vs ETFs.
• Bond and stable value funds: lower risk and lower expected return, useful as retirement approaches.

Pay attention to the expense ratio, the annual fee each fund charges. A difference between 0.05% and 0.75% a year can add up to tens of thousands of dollars over a career.

Withdrawals and early access

• Withdrawals before age 59½ are generally subject to income tax plus a 10% penalty, with some exceptions.
• The "rule of 55" can let you withdraw penalty-free from your current employer's plan if you leave that job in or after the year you turn 55.
• Many plans allow 401(k) loans. They can be useful in a pinch, but if you leave your job, any unpaid balance may come due quickly or be treated as a taxable distribution.
• Traditional 401(k)s have required minimum distributions starting at 73 (75 for those born in 1960 or later). Roth 401(k)s no longer require RMDs during the owner's lifetime.

What happens to your 401(k) when you change jobs?

You usually have four options: leave it in the old plan (if allowed), roll it into your new employer's plan, roll it into an IRA, or cash it out. Cashing out is usually the worst choice because of taxes and penalties. A direct rollover, where the money goes straight from one account to another, avoids withholding and keeps your savings growing.

How much should you contribute?

1. Step 1: enough to get the full employer match.
2. Step 2: pay off high-interest debt and build an emergency fund.
3. Step 3: aim for around 15% of your pay for retirement, including any match. Many plans offer automatic yearly increases of 1%, which is an easy way to get there.
4. Step 4: if you can save more, consider an IRA or maxing out the 401(k).

Sources: IRS 2026 retirement plan limits; SECURE 2.0 Act provisions. We will update this guide when 2027 limits are announced.