What is a 401(k) & how can you make the most of it?

A 401(k) plan is one of the most common retirement savings options for Americans who work in the for-profit sector. If your employer offers one—or if you work for yourself—you stand to enjoy far greater financial security by learning the ins and outs of how 401(k)s work and understanding why it's generally a good idea to contribute if you're eligible.

A 401(k) is the most common type of employer-sponsored retirement plan. It helps employees save for and invest in their retirement in a way that's tax-deferred. A 401(k) is a type of defined contribution plan and named after the section of the Internal Revenue Code that lays out the laws for these plans and states how much money you can put into one. If you're trying to find tax information about 401(k) plans from the IRS, however, it's important to know that they're also called qualified plans.

Other popular types of employer-sponsored retirement accounts that work similarly to 401(k)s include 403(b)s and 457(b)s.

Get more details about retirement plan types: A simple guide to the many types of retirement accounts.

You can contribute to a 401(k) plan if your employer offers one and if you meet your employer's eligibility requirements. A federal law called the Employee Retirement Income Security Act (ERISA) protects your right to participate.

The documents you received when you accepted your job should explain the benefits your company provides, including a retirement savings plan. If you're unsure, ask your coworkers, your boss or your human resources department. If your company has an online employee benefits center, you may be able to get the information you need by logging in.

Every company that has a 401(k) plan is responsible for offering a formal document called a summary plan description detailing the plan's rules, including who is eligible to contribute. Save a copy of this document to reference later.

One common eligibility requirement involves working for the company for a certain amount of time. For example: If you're a full-time employee, you could have to work there for six months before you're allowed to contribute or receive an employer match. If you're a part-time employee, you may have to work an average of 20 hours per week or another minimum to be eligible.

Like all other types of investments, 401(k)s fall into an income tax bucket of either "tax now," "tax later" or "tax never." Among the range of 401(k)s, traditional 401(k) contributions are the most common. These plans fall into the "tax later" category, as they accumulate pretax dollars through payroll deductions during your working years but then are taxed as your withdraw the money in your retirement. This is called taking a distribution.

Your employer may also offer an option to contribute to a Roth 401(k) rather than a traditional 401(k). Withdrawals on these earnings are "tax never," as they won't be taxable if you're at least 59½ (or meet certain other conditions, including death or disability). And as long as it's been five taxable years since your first designated Roth 401(k) contribution.¹

Aside from the standard 401(k), the IRS allows for some variations suited to specific needs.

If you are a business owner and have no employees, you can contribute to a solo 401(k), also called a self-employed 401(k) or individual 401(k). A solo 401(k) is limited to business owners and spouses. It's otherwise similar to a traditional 401(k).

The SIMPLE 401(k) is a less common type. Small businesses with employees may choose it as a more streamlined alternative to administering a traditional 401(k).

If you're eligible for an employer-offered 401(k), here's why it pays to participate.

Many employers match a portion of your contributions via employee matching contributions, and some may even contribute money to your 401(k) whether you do or not in what are called non-elective contributions. To get the most out of your plan, get to know your employer's matching policy.

Let's say you make $100,000 and your employer offers a 5% match. If you have 5% of your pay ($5,000) withheld from your paycheck and put into your 401(k), your employer may also put $5,000 in your account. You'd then have a total of $10,000, which means you're effectively saving 10% of your salary for retirement. That's like getting 100% return on your investment. Plus, you won't owe Social Security, Medicare or FICA taxes on your employer's contributions.

Whether you choose Roth or traditional for your own contributions, employer contributions are traditional.

Even if your employer doesn't contribute to your 401(k), you can still reap the rewards of contributing yourself; your investment earnings grow tax-deferred. Say your account value increases from $1,000 to $1,100 from January 1 to December 31—the $100 increase is not taxable. If you experienced the same gain in a nonretirement account, it would be taxable.

Tax-deferred growth helps your account balance grow far larger than the same contributions could in a taxable account. Suppose you invested $300 a month and earned returns of 6% per year. If you put that money in a 401(k), you'd have $138,851 after 20 years. If you put that money in a taxable brokerage account, you'd only have $115,212—$23,639 less—assuming your federal marginal tax rate was 22%.

Whichever type of 401(k) you contribute to and whichever type of contributions you make, tax-deferred growth can help you generate more money for retirement.

401(k) plans have higher annual contribution limits. If you're 50 or older, you also have the option to make catch-up contributions to boost your progress towards retirement.

An employer can contribute even more to your 401(k), for a total possible contribution of up to 100% of your salary or $61,000 in 2022 or $66,000 in 2023 (whichever is lower) if you are under age 50.
Starting in 2025 participants turning 60, 61, 62 or 63 during that calendar year, the client can do the regular catchup plus an additional amount limited to $10,000 or 150% of the dollar amount which would be in effect under such clause for 2025 for eligible participants.

Before you contribute to your 401(k), keep in mind that there are reasons to be careful about how much you put in.

Once you contribute money to a 401(k), it can be difficult to get that money back before you reach age 59½. Some plans include options to borrow money from your 401(k) and repay it with interest, but your employer doesn't have to offer this feature.

Some plans allow you to take a type of early distribution called a hardship withdrawal under specific circumstances, such as having high medical expenses or needing to repair certain types of damage to your home. However, these distributions may require you to pay a 10% early withdrawal penalty. Also, if you withdraw untaxed contributions, they'll be subject to ordinary income tax.

Further, you might be surprised at how many kinds of financial emergencies don't count as a hardship. For example, the IRS doesn't classify a temporary short- or long-term disability as a hardship, even though disability typically means you're earning less and incurring more medical bills. Only total and permanent disability allows you early access to your 401(k). This is one of many reasons that disability insurance is so important.

Given these restrictions on withdrawing money before you're 59½, it's crucial to find that sweet spot—contributing enough to meet your retirement goals but not so much that you'll have problems meeting your expenses before retiring.

Once you make a contribution, you may be limited to a preselected menu of investment options. The average plan offers between eight to 12 funds. These funds might be mutual funds or exchange-traded funds. They should allow you to invest in a variety of asset classes, such as large-company stocks, small-company stocks and government bonds.

For many people, not having to choose from the entire pool of investments the market offers can be a good thing. More experienced investors may prefer to have more options.

RMDs are determined by age. If you turned 72 in 2022 or earlier (born in 1950 or earlier), there is no change to RMD start age. If you were born 1951-1959, you can delay until age 73. If you were born in 1960 or later, your RMD start age is 75. Once you reach this age based on your year of birth, IRS rules generally require you to start taking money out of your 401(k) through RMDs. But if you're still working and your plan allows it, you may be able to delay taking RMDs. The IRS applies a formula to determine the amount of each annual RMD. Additionally, the IRS requires those who own 5% or more of a company to take RMDs once they turn 73. This age increases to 75 in 2033.

Some people may feel limited by RMDs requirements because they may not need to withdraw as much to cover their expenses as the IRS requires. They'd prefer to keep the money in the account where it can continue to grow tax-deferred.

Some companies automatically enroll eligible workers in their 401(k) plans. By default, the employer may redirect a certain amount of the employee's pay to the plan and put the money into a suitable investment. That said, employees have the right to opt out of automatic enrollment, change their contribution rate, and make their own investment selections.

If you've been enrolled automatically, you'll see the deductions on your pay stub. However, you may want to change your contribution rate or how your money is invested. You can do this by logging into your account through your plan administrator's website. You can also use the website to characterize your contributions as traditional or Roth and determine what percentage of your paycheck goes to each type of contribution.

If you're not already enrolled, you can begin at any point during the year as long as the employer allows and you're eligible to participate. Ask your company's human resources department how to sign up. Then, create your account on the plan administrator's website so that you can easily manage your contributions and investments.

To take a distribution, contact your plan administrator—the financial services company whose name is on your account statements. You can make your request online, by phone or by mail.

Each plan has requirements that must be met in order to allow a distribution to be sent directly to you. If your request is approved, they'll send you the money by check or direct deposit. If applicable, they will withhold taxes and remit them to the IRS. If you're borrowing from your 401(k), they'll manage your loan repayments.

You must meet specific requirements to take distributions. The requirements will depend on what the plan document allows, the type of distribution you're taking (e.g., RMD, hardship, loan) and whether you still work for your employer (these are called "in-service distributions") or not. Consult your summary plan description for details.

When you leave your job, you can roll your 401(k) balance into an IRA. You may also be able to keep your plan with your former employer or transfer your balance to your new employer's 401(k) through a direct rollover. Cashing out is another option, though financial advisors generally advise against it.

If you can afford to do so, it's a good idea to not solely rely on your 401(k) to fund your retirement. In fact, Thrivent's 2022 Retirement Readiness Survey² found that among those nearing retirement, 42% intend to rely on a mix of assets such as a 401(k), personal savings, Social Security benefits and individual retirement accounts (IRAs).

Explore supplementing your 401(k) savings with IRAs and other investments. Also, it's important to understand how much Social Security to expect so you can factor that into the right retirement amount for you.

If you do have more than one retirement account, evaluate how your accounts collectively protect you against (or overexpose you to) various tax risks—something a financial advisor can help with.

A 401(k) helps you build a foundation to shape your retirement as you'd like it. Are you ready to contribute or unsure what your next move should be? Connect with a financial advisor to learn more about retirement investment strategies and stay on track with your savings plan.