How a 401(k) Works

The plain answer

A 401(k) is a retirement account offered through an employer. You can direct part of each paycheck into the account, your employer may contribute too, and you choose investments from the plan’s menu. Contributions reduce your take-home pay, but an employer match is part of your compensation, so try to receive the full match when your budget can support it.

How it actually works

An employee deferral is money you choose to send from your pay into the plan. A traditional deferral can reduce your current taxable income, and withdrawals are generally taxable later. A Roth deferral is made after tax, and qualified withdrawals can be tax-free.

An employer contribution is money your employer adds to your account. A match is one type of employer contribution, usually based on how much you contribute under the plan’s formula. Your own deferrals are yours, while employer contributions may follow a vesting schedule, which determines when you fully own them.

The 2026 employee elective deferral limit is $24,500. If the plan permits catch-up contributions, the additional limit is $8,000 for someone age 50 or older, or $11,250 for someone ages 60 through 63. The overall additions limit is pending.

Contributing puts cash into the account, but it does not always choose the investments for you. Your plan may use a default investment if you do not make a selection. Review the available funds, fees, and risk level so the investments fit the time until you expect to use the money.

What this means for you

A higher contribution rate can help retirement saving, but it leaves less money in each paycheck. Cover required bills and keep a workable cash buffer, then contribute enough to receive the full employer match if you can. After that, use your broader priorities to decide whether to increase the contribution.

Read the plan’s summary description for its match formula, vesting schedule, investment menu, fees, and withdrawal rules. Decide between traditional and Roth deferrals based on when you want the tax benefit, while recognizing that future tax rates and your future income are uncertain.

Check your contribution election after a raise or job change. A rate that once fit your budget may need to change, and a new employer’s plan can have different rules.

Common mistakes

Do not assume enrollment, matching, or investment selection happens automatically. Confirm your contribution rate, beneficiary, tax choice, and investments after the first payroll contribution reaches the account.

Another mistake is overlooking the match formula or vesting schedule. The match is part of compensation, but contributing more than your budget can support may cause expensive debt or missed bills. Balance the match against immediate needs using a clear order of operations.

Avoid treating the balance as ordinary spending money. Early withdrawals can trigger taxes, penalties, and plan restrictions depending on the circumstances. Keep emergency savings outside the plan for near-term expenses.

Related pages

• Explore the 401(k) section
• The order of operations for your money
• Traditional vs. Roth 401(k)