Your 401(k) is likely the most powerful wealth-building tool you have access to. The employer match alone makes it the closest thing to free money you will ever get.
How a 401(k) Works
A 401(k) is an employer-sponsored retirement savings plan. Money is deducted from your paycheck before (or after) taxes and invested in funds you choose from a menu your employer provides. The account grows tax-deferred, meaning you do not pay taxes on investment gains each year. You pay taxes only when you withdraw money in retirement.
Traditional 401(k) contributions come out of your paycheck before income tax, reducing your taxable income for the year. If you earn $80,000 and contribute $10,000, you are only taxed on $70,000. The tradeoff is that every dollar you withdraw in retirement is taxed as ordinary income. This is advantageous if you expect to be in a lower tax bracket when you retire.
Many employers also offer a Roth 401(k) option. Roth contributions are made with after-tax dollars, so they do not reduce your current taxable income. However, qualified withdrawals in retirement, including all the investment growth, are completely tax-free. If you are early in your career and expect your income to grow significantly, the Roth option can save you substantial taxes over your lifetime.
The Employer Match: Free Money You Cannot Afford to Miss
Most employers offer a matching contribution. A common formula is a dollar-for-dollar match on the first 3 percent of your salary, then 50 cents on the dollar for the next 2 percent. If you earn $80,000 and contribute 5 percent ($4,000), your employer adds $3,200. That is an instant 80 percent return on your contribution before your investments earn a single penny.
Not contributing enough to get the full match is leaving compensation on the table. It is the single biggest financial mistake employees make. Even if you are paying off debt or have other financial goals, you should almost always contribute at least enough to capture the full employer match. No savings account, debt payoff strategy, or alternative investment offers a guaranteed return that competes with a 50 to 100 percent instant match.
Contribution Limits and Catch-Up Contributions
For 2025, the employee contribution limit for a 401(k) is $23,500. If you are 50 or older, you can make an additional catch-up contribution of $7,500, bringing your total to $31,000. These limits apply to the total of your Traditional and Roth 401(k) contributions combined. Your employer match does not count toward this limit.
The total limit including employer contributions is $70,000 for 2025 ($77,500 with catch-up). This higher cap matters for people with generous employer matches or those who can make after-tax contributions and do an in-plan Roth conversion, sometimes called the mega backdoor Roth strategy. Not all plans allow this, but if yours does, it is a powerful way to get more money into tax-advantaged accounts.
Vesting Schedules: When the Match Is Truly Yours
Your own contributions and their earnings are always 100 percent yours. However, employer matching contributions often have a vesting schedule. This means you earn ownership of the match gradually over time. A common schedule is 20 percent per year over five years, meaning you are fully vested after five years of service. If you leave after three years under this schedule, you keep only 60 percent of the employer match.
Some employers offer immediate vesting or cliff vesting (0 percent until a certain date, then 100 percent). Understanding your vesting schedule matters when considering a job change. If you are 80 percent vested and considering leaving, it may be worth waiting a few more months to become fully vested, especially if the match amount is significant.
Choosing Your Investments: Target-Date Funds and Beyond
Most 401(k) plans offer a selection of mutual funds, including target-date funds, index funds, bond funds, and sometimes company stock. Target-date funds are the simplest option. You pick the fund closest to your expected retirement year (such as a 2055 fund if you plan to retire around 2055), and the fund automatically adjusts its stock-to-bond ratio as you age. It starts aggressive with mostly stocks and gradually shifts toward bonds as your target date approaches.
If you prefer more control, look for low-cost index funds in your plan menu. An S&P 500 index fund or total stock market index fund paired with a bond index fund gives you broad diversification at minimal cost. Pay attention to expense ratios. A fund charging 0.80 percent annually costs eight times more than one charging 0.10 percent. Over a 30-year career, that difference can cost you tens of thousands of dollars in lost growth.
Avoid putting a large percentage of your 401(k) into your employer's stock. If the company struggles, you could lose your job and a significant portion of your retirement savings at the same time. Diversification protects you from this concentrated risk. A general guideline is to keep no more than 10 percent of your retirement portfolio in any single stock, including your employer.