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The major types of 401(k) plans are traditional 401(k)s and Roth 401(k)s. Smaller employers may offer you a SIMPLE (Savings Incentive Match Plan for Employees) 401(k) or a safe harbor 401(k) plan. If you’re an entrepreneur, you may be able to set up your own 401(k) account, too. These types of 401(k) plans have grown in popularity since the introduction of the 401(k) plan in the late 1970s and early ’80s. Nowadays, about 70 million workers participate in this type of retirement savings account. Learn more about these types of plans to decide which is right for you.
Key Takeaways
- Larger employers typically offer both traditional and Roth 401(k)s.
- Smaller employers may favor SIMPLE (Savings Incentive Match Plan for Employees) and safe harbor 401(k) plans, which can be less complex and less costly to administer.
- Solo entrepreneurs can set up a 401(k) just for themselves.
5 Types of 401(k)s and How They Work
All 401(k)s are defined contribution plans. They’re funded by employee contributions. Sometimes employers contribute, too.
With a 401(k), the amount of money that employees will have available for retirement is determined by how much they contributed to the plan and how well the investments in their account have performed over the years.
There are several different types of 401(k) plans. These are the ones you are most likely to encounter as either an employee or an employer.
Traditional 401(k)
This is what most people probably think of as a 401(k). The employee contributes pre-tax money to their account each pay period, usually through regular payroll deductions. That money goes into the investments, typically mutual funds, that they’ve chosen from the plan’s offerings.
The maximum that employees can contribute is set by law. For 2025, it is $23,500 a year for anyone under age 50 or $31,000 for those 50 or older—unless you’re 60, 61, 62 or 63. In that case, you can contribute up to $34,750.
On top of that, many employers will make a matching contribution, such as 50 cents per dollar of the employee’s contributions, up to 6% of the employee’s salary.
With a traditional 401(k), the money that the employee contributes is not immediately taxed. Instead, the amount of their contribution lowers their taxable income for the year. So, for example, an employee who makes $50,000 a year and contributes $10,000 to their 401(k) plan will pay income taxes only on $40,000 of their income that year. The account’s earnings will also grow tax-deferred until they’re eventually withdrawn.
When the employee makes withdrawals (often referred to as distributions) from the account, that money will be taxed as regular income. In addition, because 401(k)s are intended for retirement, employees generally can’t withdraw money before age 59½ without paying a 10% early withdrawal penalty. There are, however, some exceptions to that rule.
Traditional 401(k) plans are also subject to required minimum distribution (RMD) rules. Account owners must take RMDs each year starting at age 73. (Your birth year may mean that your RMDs started earlier. Internal Revenue Service (IRS) Publication 590-B has tables and worksheets that you can use to calculate your RMDs.)
Note
In addition to 401(k)s, other types of defined contribution retirement plans include 403(b) plans for schools and nonprofits, 457 plans for government workers, and profit-sharing plans in the corporate world.
Roth 401(k)
The Roth 401(k), sometimes called a designated Roth account, is like a traditional 401(k) but with one key difference: Contributions don’t receive an upfront tax break, but withdrawals will be tax free if the employee meets certain requirements. Specifically, they must generally be 59½ or older and have had the Roth account for at least five years; however, as with traditional 401(k)s, there are exceptions. Contributions to a Roth 401(k)—as opposed to the account’s earnings—can be withdrawn tax free at any time because they have already been taxed.
Some employers offer both traditional and Roth 401(k) options. Employees can, if they wish, split their contributions between the two types, but their maximum total contribution (in 2025) can’t exceed $23,500 a year for anyone under age 50 or $31,000 for those 50 or older—unless you’re age 60, 61, 62 or 63. In that case, you can contribute up to $34,750.
Roth 401(k)s were subject to the same RMD rules as traditional 401(k)s before 2024. Now, RMDs are no longer required from designated Roth 401(k)s during the account owner’s lifetime, per the SECURE 2.0 Act of 2022.
SIMPLE 401(k)
SIMPLE (Savings Incentive Match Plan for Employees) 401(k) plans are designed for businesses with 100 or fewer employees.
With a SIMPLE 401(k) plan, employees can contribute up to $16,500 (in 2025) if they’re under age 50 or $20,000 if they’re 50 or older. The exception is if you’re age 60, 61, 62 or 63. In that case, you can contribute up to $21,750. As with a traditional 401(k), that money isn’t taxed as income until it’s eventually withdrawn from the plan.
The employer must make either a matching contribution of up to 3% of each employee’s pay for those who contribute to the plan or a nonelective contribution of 2% for all eligible employees, regardless of whether they participate in the plan.
Like traditional and Roth 401(k)s, SIMPLE 401(k)s can be subject to early withdrawal penalties before age 59½ and to required minimum distributions after age 73.
Safe Harbor 401(k)
Safe harbor is a legal term for a provision in the law that exempts a person or company from certain regulations if they meet other requirements. A safe harbor 401(k) allows employers to skip the nondiscrimination tests that most 401(k) plans are subject to. Nondiscrimination tests are intended to ensure that plans do not discriminate in favor of highly-compensated employees in terms of employer matches or other benefits. Because safe harbor 401(k)s are easier to administer, they are especially popular with small businesses.
In return, employers with safe harbor 401(k)s must make annual contributions to every eligible employee’s plan, regardless of whether the employees themselves contribute. In addition, that money is immediately vested, regardless of how long the employee has been with the
company.
(Other types of 401(k) plans often have vesting requirements for their employer contributions, while employee contributions are always immediately vested.)
Employers can make their required contributions in one of three ways:
- Nonelective contribution: The employer contributes an amount equal to 3% of compensation on behalf of each non-highly compensated employee. Employees are not required to contribute.
- Basic match: The employer matches 100% of each non-highly compensated employee’s elective contributions, up to 3% of their compensation. Also, it matches 50% of the next 2% in compensation. So, for example, an employee who earns $50,000 a year would be eligible for a maximum match of $2,000 (100% of their first $1,500 in contributions plus 50% of the next $1,000).
- Enhanced match: The employer can base its match on up to 6% of the employee’s compensation, rather than just 5%, as with a basic match.
Aside from those differences, safe harbor 401(k)s work much like any other 401(k) and are subject to the same rules on contributions, early withdrawals, and required minimum distributions.
Warning
If you have multiple 401(k) plans, such as one with an employer and another for your own small business, your total contributions can’t exceed the maximum for a single 401(k) plan.
One-Participant 401(k)
These plans go by a variety of names, including solo 401(k), individual 401(k), and self-employed 401(k). They are designed for businesses with no employees other than the owner, plus their spouse if that person also works in the business.
Because the owner is considered both an employer and an employee of the business, they can contribute to the plan in both capacities.
As employees, they can contribute up to 100% of their compensation or net income from self-employment, with the same annual contribution limit as traditional and Roth 401(k) plans: for 2025, it’s $23,500 a year for anyone under age 50 or $31,000 for those 50 or older. There’s an exception if you’re 60, 61, 62 or 63. If you are, you can contribute up to $34,750.
As their own employers, they can also make additional, nonelective contributions. The maximum depends on how their business is set up for tax purposes (S corporation vs. self-employed sole proprietor, for example).
In total, as employer and employee, the business owner can contribute as much as $70,000 to their 401(k) plan (for 2025), plus another $7,500 if they’re 50 or older (or $11,250 if they’re 60, 61, 62 or 63).
Spouses who earn income from the business can also contribute to a one-participant 401(k), up to the same maximums, and they are eligible for the same additional employer contribution.
One-participant 401(k)s can be either traditional or Roth plans and are subject to the same rules as those plans for early withdrawals and required minimum distributions.
Other Retirement Savings Vehicles
There are also other ways you can save for retirement. Individual retirement accounts (IRAs) offer a traditional option and a Roth option. You can open an IRA on your own with a broker and potentially get a tax deduction for contributing every year.
Additionally, your employer may offer a health savings account (HSA). An HSA is a place where you can save pre-tax money every month and use it for medical expenses. It’s often paired with a high-deductible health plan. It’s a tax-advantaged account that can be used as a retirement savings account. That’s because you can invest the funds in an HSA similar to how you would with a 401(k) or IRA. You can also leave the funds where they are and roll them over year to year if you don’t use them. And when you reach age 65, you can use the money in your HSA for other expenses, not just qualified medical expenses. (If you do so, however, you’ll pay income tax on those expenses.)
Can You Have Both a 401(k) Plan and an Individual Retirement Account (IRA)?
Yes, you can contribute to both a 401(k) plan at work and an individual retirement account (IRA) on your own. However, if either you or your spouse has a 401(k) plan, your traditional IRA contributions may not be tax-deductible. It depends on your tax filing status and income. For example, for married couples who file jointly, the income phase-out range is $126,000 to $146,000 if the spouse who is contributing to the IRA is covered by a workplace retirement plan, like a 401(k). (Roth IRA contributions are not tax-deductible.)
How Does Vesting Work in a 401(k) Plan?
Employee contributions to a 401(k) plan vest immediately, meaning that they belong to the employee from day one. Employer matching contributions can work differently, depending on the type of plan. With some types, such as safe harbor 401(k)s, matching contributions vest right away. With other types, such as traditional 401(k)s, employers can set different rules if they wish to. For example, the employer match might vest only after three years of service or vest gradually over a six-year period. If the employee parts ways with their employer before that period is up, they lose access to those matching contributions.
What Is Automatic Enrollment, and How Does It Work?
Automatic enrollment is a provision in some 401(k) plans that allows employers to defer a portion of an employee’s wages and deposit the money into a 401(k) account on their behalf. Employees can opt out if they wish to do so. Plans with this provision are sometimes referred to as automatic enrollment 401(k)s. Automatic enrollment (with an opt-out provision for those who don’t want to join) is mandatory for newly created 401(k) plans for plan years beginning after December 31, 2024.
Are 401(k) Plans Federally Insured?
No, unlike most bank and credit union accounts in the U.S., 401(k) plans are not covered by the Federal Deposit Insurance Corp. (FDIC).
In addition, the money you save in a 401(k) is invested. Investments are always subject to losses, and gains are never guaranteed.
The Bottom Line
There are several types of 401(k) plans that employers may offer their workers. Traditional and Roth plans are most common among larger employers, while SIMPLE and safe harbor plans are often found at small businesses. Business owners without other employees can also open one-participant 401(k) plans. If you have any questions about your plan, reach out to your employer or plan administrator.