Question 1

What is a 401(k) and how does it work?

Accepted Answer

A 401(k) is an employer-sponsored retirement savings plan that lets you contribute a portion of your paycheck before taxes are taken out. Your contributions and investment earnings grow tax-deferred, meaning you don't pay income tax until you withdraw the money in retirement. Many employers also offer a matching contribution, which is essentially free money added to your account. Funds are typically invested in a mix of mutual funds, index funds, or target-date funds offered by the plan.

Question 2

What is the 401(k) contribution limit for 2025?

Accepted Answer

For 2025, the IRS allows employees to contribute up to $23,500 per year to a 401(k). If you are age 50 or older, you can make an additional catch-up contribution of $7,500, bringing your total limit to $31,000. These limits apply to employee elective deferrals only. Employer matching contributions are on top of this, with a combined employee + employer limit of $70,000 for 2025. The IRS typically adjusts these limits annually for inflation.

Question 3

How does employer 401(k) matching work?

Accepted Answer

Employer matching means your company contributes additional money to your 401(k) based on your own contributions. A common structure is '50% match up to 6% of salary,' which means if you earn $75,000 and contribute at least 6% ($4,500/year), your employer adds 50% of that amount ($2,250/year). Different employers have different match formulas and vesting schedules. Vesting determines when the employer contributions become fully yours — it may be immediate or phased over several years. Always contribute at least enough to get the full employer match, as it's one of the best guaranteed returns available.

Question 4

What rate of return should I use for 401(k) projections?

Accepted Answer

The appropriate rate of return depends on your investment mix. Historically, a 100% stock portfolio (e.g., S&P 500 index fund) has averaged around 10% annually before inflation, or roughly 7% after inflation. A balanced portfolio of stocks and bonds might average 6–8% before inflation. Most financial planners suggest using 6–7% as a conservative estimate for long-term planning. Keep in mind that past performance does not guarantee future results, and actual returns will fluctuate year to year. The older you are and the closer to retirement, the more conservative your allocation (and expected return) typically should be.

Question 5

What is the difference between traditional and Roth 401(k)?

Accepted Answer

With a traditional 401(k), contributions are made pre-tax, reducing your taxable income today, and withdrawals in retirement are taxed as ordinary income. With a Roth 401(k), contributions are made with after-tax dollars, so there's no upfront tax break, but qualified withdrawals in retirement are completely tax-free, including all the growth. If you expect to be in a higher tax bracket in retirement than you are now, a Roth 401(k) may be advantageous. Many plans allow you to split contributions between traditional and Roth. This calculator focuses on traditional 401(k) projections, but the growth math is the same for both.

Question 6

Can I withdraw from my 401(k) before retirement?

Accepted Answer

Yes, but early withdrawals come with significant costs. If you withdraw money before age 59½, you generally owe income tax on the amount plus a 10% early withdrawal penalty. For example, if you're in the 22% tax bracket and withdraw $10,000, you could owe $3,200 in taxes and penalties. There are exceptions to the penalty (such as disability, certain medical expenses, or substantially equal periodic payments), but these are narrow. You can also borrow from your 401(k) through a loan, which must be repaid with interest. Most financial advisors recommend avoiding early withdrawals to preserve the power of compound growth.

Question 7

When should I start contributing to my 401(k)?

Accepted Answer

The sooner the better — compound growth is most powerful over long time horizons. Starting at age 25 versus age 35 can more than double your retirement balance, even with the same monthly contributions. A common guideline is to contribute at least enough to capture the full employer match immediately, then work toward saving 15% of your gross income for retirement (including any employer match). If you're starting later, take advantage of catch-up contributions once you turn 50. Even small increases in your contribution rate, made consistently, can have a dramatic impact on your final balance thanks to compounding.

Age	Your Contributions	Employer Match	Growth	Total Balance
36	$6,000	$3,000	$3,909	$62,909
37	$12,000	$6,000	$8,751	$76,751
38	$18,000	$9,000	$14,594	$91,594
39	$24,000	$12,000	$21,510	$107,510
40	$30,000	$15,000	$29,576	$124,576
41	$36,000	$18,000	$38,876	$142,876
42	$42,000	$21,000	$49,499	$162,499
43	$48,000	$24,000	$61,540	$183,540
44	$54,000	$27,000	$75,103	$206,103
45	$60,000	$30,000	$90,297	$230,297

401(k) Calculator

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Year-by-Year Breakdown

2025 IRS 401(k) Contribution Limits

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