401(k) Fundamentals

What Is a 401(k)?

A 401(k) is an employer-sponsored retirement plan that can help you save for the future through payroll contributions, potential employer contributions and investments.

Payroll Contributions
Long-Term Growth
The Basics

A 401(k) is a retirement savings account offered through an employer.

A 401(k) is a type of defined contribution retirement plan. Eligible employees can generally direct part of their compensation into an individual account through payroll deductions.

Depending on the plan, an employer may also contribute money through matching or other employer contributions. The money in the account can be invested in the options available through the plan.

Unlike a pension that promises a specified retirement benefit, a 401(k) account's future value depends on contributions, investment performance and applicable fees.

Learn how a 401(k) works →
How It Works

The basic 401(k) process

Your plan connects payroll contributions, employer contributions and investments inside one retirement account.

01

You contribute

You choose an amount or percentage of your pay to contribute if you are eligible under your employer's plan.

02

Your employer may contribute

Some plans provide matching or other employer contributions according to the plan's terms.

03

Your money is invested

Your account can be invested among the options offered by your particular retirement plan.

04

Your balance changes over time

Contributions, investment gains or losses and applicable fees can affect the value of your account.

Know The Components

What makes up a 401(k)?

Understanding each part makes it easier to read your plan information and make sense of your retirement account.

Contributions

Money you elect to put into the plan through payroll deductions, subject to the plan and applicable tax rules.

Explore contributions →

Vesting

Your own contributions are fully vested, while some employer contributions may be subject to a vesting schedule.

Learn about vesting →
Tax Treatment

Traditional and Roth 401(k) contributions

Some 401(k) plans offer both pre-tax and designated Roth contribution options.

Traditional 401(k)

Traditional 401(k) contributions are generally made through pre-tax elective deferrals. Federal income tax treatment generally occurs when money is distributed, subject to applicable rules.

  • Contributions generally reduce current federal taxable income.
  • Investment earnings generally remain tax-deferred until distribution.
  • Actual tax treatment depends on the type of distribution and applicable rules.

Roth 401(k)

If your employer's plan offers a designated Roth account, Roth contributions are included in gross income when contributed. Qualified distributions can generally be tax-free.

  • Roth contributions are made with after-tax income.
  • Qualified distributions can receive tax-free treatment.
  • The plan must offer a designated Roth account for this option to be available.
Saving Through Work

Contributions are the starting point

Your contribution rate, employer contribution and the rules of your specific plan all matter when evaluating your savings.

Contribution Limits

Federal rules limit certain employee elective deferrals. The applicable limits can change over time.

See contribution limits →

Employer Match

A plan may provide matching contributions based on the employee's elective deferrals and the plan's formula.

Understand the match →

Calculate Your Savings

Explore different contribution, employer match and growth assumptions with our interactive calculators.

Open 401(k) calculators →
Your Specific Plan Matters

Not every 401(k) works exactly the same way

Federal rules establish important requirements, but your employer's plan document determines many of the details that apply to you.

Check your plan information

Your Summary Plan Description and other plan documents can explain eligibility, contribution options, matching formulas, vesting, investment choices and distribution procedures.

  • Eligibility requirements
  • Employer contribution formula
  • Vesting schedule
  • Available investment options
  • Distribution and withdrawal rules

Why the details matter

Two employees at different companies can have different contribution options, employer matching formulas, investment menus, fees and vesting provisions.

Before making decisions based on a general explanation, review your plan documents and the information supplied by your employer or plan administrator.

Want to see the numbers?

Use our calculators to explore how contributions, employer matching, investment growth and retirement timing can affect an estimated 401(k) balance.

Compare different scenarios

Explore contribution, growth, employer match, Roth and retirement scenarios from one calculator hub.

FAQ

401(k) questions, answered

Quick answers to common questions about workplace retirement plans.

A 401(k) is a defined contribution retirement plan that allows eligible employees to contribute part of their compensation to an individual retirement account through an employer's plan. The plan may also allow employer contributions and provide investment options.
You generally elect how much of your pay to contribute, and the contribution is made through payroll. Depending on the plan, your employer may contribute as well. The account is then invested according to the plan's available investment options, and the account value changes over time.
No. A 401(k) is an employer-sponsored retirement plan, so availability depends on whether your employer offers a 401(k) plan and whether you meet that plan's eligibility requirements.
No. Employer matching depends on the specific plan. Some employers provide matching contributions, while plan designs can also include other types of employer contributions.
Your own elective deferrals are fully vested. Employer contributions can be subject to a vesting schedule, depending on the plan.
Some 401(k) plans offer a designated Roth account. Roth contributions are included in gross income when contributed, while qualified distributions can generally receive tax-free treatment.
Federal contribution limits apply and can change from year to year. Your specific plan may also have additional rules or limitations. See the current 401(k) contribution limits guide for current information.
401(k) plans are subject to distribution rules, and plans do not necessarily allow every type of distribution. Your plan document determines which distribution options are available to you. Learn about 401(k) withdrawals .

Start understanding your 401(k) today.

Learn the fundamentals, explore your options and use interactive calculators to understand how different retirement scenarios may affect your future savings.

Educational Disclaimer: 401k.blog provides general educational information about 401(k) plans and retirement planning. This information is not individualized financial, investment, tax or legal advice. Retirement plans have different rules and features, so review your plan documents and consult an appropriately qualified professional when you need advice for your circumstances. Calculator results on 401k.blog are estimates for educational purposes and are not guarantees of future investment performance or retirement income.