Is a SIMPLE IRA the Same as a 401(k)? Limits, Match, and Vesting

A SIMPLE IRA and a 401(k) are both payroll-deduction retirement plans with tax advantages, but they are not the same plan. The core difference in the SIMPLE IRA vs. 401(k) comparison is that a 401(k) lets employees save far more each year and gives employers flexibility over contributions, while a SIMPLE IRA is cheaper to run, requires the employer to contribute every year, and is available only to businesses with 100 or fewer employees. For 2026, the employee deferral limit is $17,000 in a SIMPLE IRA compared with $24,500 in a 401(k), and the gap widens once employer contributions and catch-ups enter the picture.¹

Who Can Offer Each Plan

A SIMPLE IRA is restricted to employers with 100 or fewer employees who earned at least $5,000 in the previous calendar year. That headcount includes full-time, part-time, seasonal, and leased workers.² A 401(k) has no size limit. A solo consultant and a company with 50,000 employees can both sponsor one.³

Employee eligibility differs too. To join a SIMPLE IRA, a worker must have earned at least $5,000 in any two prior calendar years (not necessarily consecutive) and reasonably expect to earn that much in the current year.² A 401(k) typically requires an employee to be at least 21 and to complete a year of service, generally 1,000 hours in 12 months.³ Starting in 2026, SECURE 2.0 also opens 401(k) eligibility to long-term part-time workers who log at least 500 hours a year for two consecutive years.⁴ SIMPLE IRAs have no hours-worked requirement. Meet the $5,000 compensation test and you are in.

2026 Contribution Limits

The difference in how much you can put away each year is one of the clearest reasons larger businesses pick 401(k) plans.

Employee deferrals: $17,000 in a SIMPLE IRA, $24,500 in a 401(k).⁵
Standard catch-up (age 50+): $4,000 in a SIMPLE IRA, $8,000 in a 401(k).¹
Super catch-up (ages 60 through 63): $5,250 in a SIMPLE IRA, $11,250 in a 401(k), replacing the standard catch-up for those ages.¹

SECURE 2.0 added a sweetener for the smallest businesses. Employers with 25 or fewer employees can offer SIMPLE IRA deferral limits set at 110% of the standard amount. For 2026 that works out to $18,700 in employee deferrals and a $4,400 standard catch-up. A participant cannot stack both the 110% increase and the super catch-up for ages 60 through 63.

Once employer contributions are added, the 401(k) advantage grows. A 401(k) allows total annual contributions of $72,000 in 2026 across employee deferrals, employer matching, and profit sharing, not counting catch-up amounts.¹ A SIMPLE IRA has no equivalent combined cap, but its structure limits total contributions to the $17,000 deferral plus a modest employer match or 2% nonelective contribution.

What the Employer Has to Contribute

This is where the two plans diverge most sharply for business owners. A SIMPLE IRA requires the employer to contribute every year, with no exceptions. The employer picks one of two formulas:

A dollar-for-dollar match on each participating employee’s deferral up to 3% of that employee’s compensation.
A 2% nonelective contribution for every eligible employee (compensation capped at $360,000 in 2026), regardless of whether the employee defers anything.²

A traditional 401(k) is more flexible. Matching contributions are common but discretionary. A business can match generously in strong years and scale back or skip contributions during lean ones. A Safe Harbor 401(k) is the exception: the employer commits to specific matching formulas in exchange for skipping annual nondiscrimination testing.

Vesting

In a SIMPLE IRA, everything belongs to the employee immediately. Employee deferrals and every dollar of employer contributions are 100% vested from day one. There is no waiting period and no risk of forfeiting employer money if the employee leaves.

A 401(k) fully vests the employee’s own deferrals right away, but employers can impose a vesting schedule on matching and profit-sharing contributions. A cliff schedule might give you 0% of employer contributions until three years of service, at which point you become 100% vested at once. A graded schedule vests you gradually over six years.⁶ Leave before you are fully vested and you forfeit the unvested portion. Check your plan’s vesting schedule before making any job-change decision.

Roth Options in 2026

401(k) plans have offered Roth employee deferrals for years, letting participants pay tax now for tax-free withdrawals later. SIMPLE IRAs are catching up. Starting with the 2026 plan year, employers can allow Roth salary deferrals into SIMPLE IRAs. Qualified withdrawals (after age 59½ with the account open at least five years) come out tax-free.

Employer contributions in a SIMPLE IRA still have to go into a traditional, pre-tax account. SECURE 2.0 did create a mechanism for 401(k) plans to designate employer matching contributions as Roth, though those amounts are reported on Form 1099-R and count as taxable income to the employee in the year allocated.⁷ That Roth-employer-match option is not available for SIMPLE IRAs.

Loans, Withdrawals, and Early Penalties

Many 401(k) plans let participants borrow from their account and repay through payroll deductions with interest. Done on schedule, a loan avoids taxes and penalties. SIMPLE IRAs do not permit loans. If you need the money, you take a withdrawal, and that means income tax plus potential penalties.

The early withdrawal penalty is where a SIMPLE IRA carries an unusual sting. Withdrawals before age 59½ generally face a 10% additional tax, but money pulled from a SIMPLE IRA within the first two years of participation faces a 25% penalty.⁸ On a $20,000 withdrawal, that is $5,000 in penalties alone, on top of regular income tax. After two years, the penalty drops to the standard 10%.⁹

A 401(k) can also allow hardship distributions for specific urgent needs, including medical expenses, preventing eviction or foreclosure, tuition, funeral costs, and certain disaster losses. The amount cannot exceed what is needed to cover the hardship, and the distribution is still taxable and may face the 10% penalty.¹⁰ SIMPLE IRAs have no formal hardship category; you can withdraw for any reason, but the tax and penalty rules above apply unless you qualify for a standard exception like disability or a first-time home purchase.

Administrative Burden

Running a 401(k) involves real overhead. Plan sponsors must conduct annual nondiscrimination testing (the Actual Deferral Percentage and Actual Contribution Percentage tests) to verify that rank-and-file contributions stay in line with owner and highly compensated employee contributions.¹¹ Failing the tests means refunding excess contributions to highly compensated employees or making additional contributions for everyone else. Plans also file Form 5500 annually with the Department of Labor. Safe Harbor 401(k) plans avoid the testing but still require Form 5500 filing and plan document maintenance. Most employers hire a third-party administrator, adding ongoing cost. Annual recordkeeping and administration fees for a small business 401(k) commonly run from several hundred to several thousand dollars.

A SIMPLE IRA sidesteps nearly all of this. No nondiscrimination testing. No Form 5500. The employer adopts a plan document (IRS Form 5304-SIMPLE or 5305-SIMPLE), notifies employees annually, and makes contributions. For a ten-person business without a dedicated HR department, that gap in workload is often the deciding factor.

One other requirement to know: SECURE 2.0 mandates automatic enrollment for most new 401(k) plans, with a default deferral between 3% and 10% that escalates by 1% a year up to at least 10% but no more than 15%. Employees can opt out. Plans with fewer than 10 employees are exempt, and only plans established after December 29, 2022, are subject to the mandate. SIMPLE IRAs can offer automatic enrollment voluntarily.¹²

Which Plan Fits Which Business

The right choice comes down to size, budget, and how much control you want.

A SIMPLE IRA works well for a business with fewer than 100 employees that wants a low-maintenance retirement benefit, is comfortable with mandatory annual employer contributions, and doesn’t need loans or hardship distributions. The trade-off is lower savings capacity and the 25% early-withdrawal penalty during the first two years.

A 401(k) makes sense when a business wants higher contribution ceilings, discretionary matching, participant loans, hardship distributions, or Roth employer matching. It also scales to any size. The cost is real: annual testing (or Safe Harbor commitments to avoid it), Form 5500 filing, and ongoing plan management.

SECURE 2.0 has narrowed the gap in several ways. Roth SIMPLE IRA deferrals, the super catch-up, the 110% limits for the smallest employers, and student loan matching (available in both plan types)¹³ all make SIMPLE IRAs more competitive than they were. The 401(k) still offers meaningfully higher contribution limits and more structural flexibility. For a business near the 100-employee threshold, the decision usually turns on whether the administrative cost of a 401(k) is worth the higher limits and additional features your workforce will actually use.

1
Internal Revenue Service. COLA Increases for Dollar Limitations on Benefits and Contributions
2
Internal Revenue Service. Retirement Plans FAQs Regarding SIMPLE IRA Plans
3
Internal Revenue Service. 401(k) Plan Qualification Requirements
4
Internal Revenue Service. Notice 2024-73
5
Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
6
Internal Revenue Service. Issue Snapshot – Vesting Schedules for Matching Contributions
7
Internal Revenue Service. SECURE 2.0 Act Impacts How Businesses Complete Forms W-2
8
Internal Revenue Service. SIMPLE IRA Withdrawal and Transfer Rules
9
Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions
10
Internal Revenue Service. Retirement Plans FAQs Regarding Hardship Distributions
11
Internal Revenue Service. 401(k) Plan Fix-It Guide – The Plan Failed the 401(k) ADP and ACP Nondiscrimination Tests
12
Internal Revenue Service. Retirement Topics – Automatic Enrollment
13
Internal Revenue Service. Guidance Under Section 110 of the SECURE 2.0 Act With Respect to Matching Contributions Made on Account of Qualified Student Loan Payments (Notice 2024-63)