How Does a 401(k) Work?
A 401(k) connects your paycheck, retirement contributions, employer contributions and investments in one workplace retirement plan. Here's how the process works from contribution to retirement.
A 401(k) turns part of your paycheck into long-term retirement savings.
A 401(k) is a defined contribution retirement plan. If you are eligible under your employer's plan, you can generally elect to have part of your compensation contributed to your individual account.
The process is straightforward: you contribute → your employer may contribute → the money is invested → the account value changes over time → distributions are made according to applicable rules.
Unlike a traditional pension that promises a specified benefit, a defined contribution plan does not promise a specific retirement balance. The eventual account value depends on contributions, investment performance and fees.
Read: What Is a 401(k)? →How a 401(k) works
From your paycheck to your retirement account, these are the main parts of the process.
Become eligible
Your employer's plan establishes eligibility and participation requirements.
Choose contributions
You generally choose how much of your pay to defer into the plan, subject to applicable rules.
Employer may contribute
Your employer may provide matching or other contributions under the plan's terms.
Invest the account
Contributions can be invested among the options offered by your particular plan.
Access the money
Distributions are governed by the plan and applicable retirement and tax rules.
Where does the 401(k) contribution come from?
Employee contributions are generally made through payroll, so your retirement savings can happen automatically each pay period.
Employee contribution
You generally choose a percentage or, where permitted, a dollar amount to be deducted from your paycheck and contributed to the plan.
What happens next?
The contribution is deposited into your retirement account and can then be invested according to the options available through your plan.
Your employer may add money too
Employer contributions depend on your specific plan. Matching contributions are generally based on the employee's contributions and the plan's matching formula.
Matching contributions
Some employers match part of what employees contribute, according to a formula specified by the plan.
Employer match guide →Other employer contributions
A plan may also provide employer contributions that are not directly based on the employee's deferral.
Employer contributions →Vesting
Your own contributions are immediately vested. Employer contributions can have separate vesting rules depending on the plan.
Learn about vesting →What happens to the money in your 401(k)?
Contributions are generally invested using the options provided by your retirement plan. Your account value can rise or fall based on investment performance.
Investment Options
Learn about the funds and other investment choices that may be available in a workplace retirement plan.
Explore investment options →Index Funds
Understand how index funds work and where they can fit within a plan's investment menu.
Learn about index funds →Target-Date Funds
See how target-date funds are designed around an expected retirement timeframe.
Explore target-date funds →Diversification
Learn why diversification is commonly considered when constructing an investment portfolio.
Learn about diversification →Investment Costs
Investment expenses can affect the amount that remains in your account over time.
Understand expense ratios →Rebalancing
Learn what portfolio rebalancing means and how it relates to the investments available in your plan.
Explore rebalancing →How taxes fit into a 401(k)
Tax treatment depends on whether contributions are traditional, Roth or another type permitted by the plan.
Traditional 401(k)
Traditional elective deferrals are generally made before federal income tax is applied to the deferred amount. Taxes generally apply when taxable distributions are made.
Roth 401(k)
Designated Roth contributions are included in taxable income when contributed. Qualified distributions can generally receive tax-free treatment.
What does vesting mean?
Vesting determines when you have a nonforfeitable right to employer-provided contributions.
Your contributions
- ✓ Your own 401(k) contributions are immediately 100% vested.
- ✓ Earnings attributable to your contributions are also yours.
- ✓ Leaving an employer does not generally cause you to forfeit your vested employee contributions.
Employer contributions
- ✓ Employer contributions may follow a vesting schedule.
- ✓ The exact schedule depends on the plan.
- ✓ Safe harbor and certain other plans can have different vesting requirements.
401(k) fees can affect your account
A retirement account can have investment and administrative expenses. Understanding the costs in your plan can help you read your retirement statements more effectively.
Plan Fees
Learn about fees associated with administering and operating a workplace retirement plan.
Explore plan fees →Investment Fees
Investment expenses can vary between the options available inside a plan.
Investment fee guide →All 401(k) Fees
Review the broader 401(k) fees and costs cluster.
View fee resources →What happens if you leave your job?
Leaving an employer does not automatically mean your 401(k) disappears. Your options depend on your plan and circumstances.
Review your account
Check your current balance, vested employer contributions, investments and plan information.
Review your available options
Depending on the circumstances, options can include leaving the money in the former employer's plan, rolling it to another eligible retirement plan or taking a distribution.
Consider rollover rules
Direct and indirect rollovers have different procedures and tax considerations.
Explore 401(k) rollovers →Understand distributions
Taking money out can have tax consequences and may be subject to additional rules depending on the type and timing of the distribution.
Explore 401(k) withdrawals →Put the concepts into numbers
Explore different 401(k) scenarios with our calculator collection.
401(k) Calculator
Estimate a future 401(k) balance using contributions, employer matching and growth assumptions.
Calculate →Match Calculator
Estimate employer matching contributions based on your salary and contribution rate.
Calculate match →Growth Calculator
See how contributions and investment growth could affect a projected account balance.
Calculate growth →Explore the 401(k) ecosystem
Go deeper into contributions, Roth accounts, investing, rollovers, retirement and other 401(k) topics.
How does a 401(k) work? Common questions
Now see what your 401(k) could look like.
Use the 401(k) calculator to explore contributions, employer matching, investment growth and estimated future balances.
Educational Disclaimer: 401k.blog provides general educational information about 401(k) plans and retirement planning. This content is not individualized financial, investment, tax or legal advice. Plan features, eligibility, contribution rules, vesting, investment options, fees and distribution provisions can vary. Review your plan documents and consult a qualified professional for advice regarding your individual circumstances.