Small Business Retirement Plans: 401(k) vs. SEP IRA vs. SIMPLE IRA

More than half of American workers at small businesses have no access to an employer-sponsored retirement plan. If you're a small business owner, offering a retirement plan isn't just a perk—it's a powerful tool for attracting talent, reducing your tax burden, and building your own financial future. But with several plan types available, choosing the right one can feel overwhelming.

This guide breaks down the three most popular small business retirement plans—401(k), SEP IRA, and SIMPLE IRA—so you can find the best fit for your business size, budget, and goals.

Why Small Businesses Should Offer Retirement Plans

Before diving into the specifics, here's why setting up a retirement plan deserves a spot near the top of your priority list:

• Tax advantages: Employer contributions are tax-deductible business expenses, and many plans offer additional tax credits for small businesses.
• Employee retention: A retirement benefit significantly reduces turnover. Studies show that employees with retirement plans are 40% less likely to leave their jobs.
• Your own retirement: As a business owner, these plans let you save aggressively for your own future while benefiting from tax-deferred or tax-free growth.
• SECURE 2.0 tax credits: Small businesses with up to 50 employees can receive tax credits covering 100% of plan startup costs (up to $5,000 per year for three years), plus an additional credit for employer contributions.

The Three Main Plan Types at a Glance

Here's a quick comparison before we go deeper:

Feature	401(k)	SEP IRA	SIMPLE IRA
Best for	Businesses wanting flexibility	Self-employed and small teams	Businesses with up to 100 employees
2026 employee contribution limit	$24,500	N/A (employer-funded only)	$17,000
2026 total contribution limit	$72,000	$72,000 (or 25% of compensation)	$17,000 + employer match
Employer contribution required?	Depends on plan type	No	Yes
Administrative complexity	Higher	Very low	Low
Catch-up contributions (50+)	$8,000	N/A	$4,000
Super catch-up (ages 60–63)	$11,250	N/A	$5,250

401(k) Plans: Maximum Flexibility and Higher Limits

How It Works

A 401(k) plan allows employees to defer a portion of their salary into a retirement account on a pre-tax (traditional) or after-tax (Roth) basis. Employers can also make matching or profit-sharing contributions.

For 2026, employees can contribute up to $24,500 in elective deferrals. When you add employer profit-sharing contributions, the total cap reaches $72,000 per participant (or $80,000 for those age 50 and older with catch-up contributions).

Solo 401(k) for Self-Employed Owners

If you're self-employed with no employees (other than a spouse), a Solo 401(k) is often the best option. You wear both hats—employee and employer—which means you can contribute on both sides:

• Employee deferrals: Up to $24,500
• Employer profit-sharing: Up to 25% of net self-employment income
• Combined maximum: $72,000 (under age 50)

This dual contribution structure often allows Solo 401(k) participants to save significantly more than they could with a SEP IRA, especially at lower income levels.

Pros

• Highest contribution limits among all plan types
• Roth option available for tax-free growth
• Loan provisions possible
• Flexible employer matching formulas
• Employees can choose their own contribution amount

Cons

• Higher administrative costs (annual filing of Form 5500, possible third-party administration fees)
• More complex to set up and maintain
• Annual nondiscrimination testing required for traditional 401(k) plans (Safe Harbor plans can avoid this)

Best For

Businesses that want maximum flexibility, high contribution limits, and the ability to offer Roth options. Also ideal for self-employed individuals through the Solo 401(k).

SEP IRA: Simplicity for Employer-Funded Plans

How It Works

A Simplified Employee Pension (SEP) IRA is exactly what it sounds like—simple. The employer makes all contributions directly into individual IRAs set up for each eligible employee. There are no employee salary deferrals.

For 2026, employers can contribute up to the lesser of 25% of each employee's compensation or $72,000.

Key Rules

• Uniform contribution percentage: If you contribute 15% of your own compensation, you must contribute 15% for every eligible employee.
• Eligibility: Employees who are 21 or older, have worked for you in 3 of the last 5 years, and earned at least $750 in compensation must be included.
• No annual contributions required: You can vary contributions year to year or skip them entirely in lean years.

Pros

• Extremely easy to set up (complete IRS Form 5305-SEP)
• No annual IRS filings required
• Flexible contribution amounts—contribute more in good years, less in tough ones
• High contribution ceiling ($72,000)
• Low to no administrative costs

Cons

• Employer funds everything—no employee salary deferrals
• Must contribute the same percentage for all eligible employees
• No Roth option
• No loan provisions
• No catch-up contributions for older workers

Best For

Self-employed individuals or small business owners who want a dead-simple plan with high contribution limits and don't need employee salary deferrals. Particularly attractive for businesses with few or no employees.

SIMPLE IRA: The Middle Ground

How It Works

A Savings Incentive Match Plan for Employees (SIMPLE) IRA combines simplicity with employee participation. Employees make salary deferral contributions, and employers are required to make either matching or non-elective contributions.

For 2026, the employee deferral limit is $17,000, with a $4,000 catch-up for those 50 and older (or $5,250 for ages 60–63 under the SECURE 2.0 super catch-up provision).

Employer Contribution Options

You must choose one of two formulas each year:

1. Dollar-for-dollar match: Match employee contributions up to 3% of their compensation (can be reduced to 1% in up to 2 out of 5 years).
2. Non-elective contribution: Contribute 2% of each eligible employee's compensation regardless of whether they contribute.

Pros

• Easy to set up and maintain
• No annual IRS filings
• Employees participate through salary deferrals, increasing engagement
• Lower employer cost compared to SEP IRA (match only applies to contributing employees)
• Mandatory employer contributions are modest

Cons

• Lower contribution limits than 401(k) or SEP IRA
• Must have 100 or fewer employees
• Cannot maintain any other employer-sponsored retirement plan simultaneously
• No Roth option (though SECURE 2.0 may expand this)
• 25% early withdrawal penalty in the first two years (vs. the standard 10%)
• No loan provisions

Best For

Small businesses with up to 100 employees who want an easy-to-administer plan that encourages employee participation without the complexity and cost of a 401(k).

How to Choose the Right Plan

Consider Your Business Size

• Solo or spouse-only: Solo 401(k) usually wins on contribution potential. SEP IRA is a simpler alternative.
• 2–10 employees: SEP IRA if you want employer-only funding. SIMPLE IRA if you want employees to contribute too.
• 11–100 employees: SIMPLE IRA for simplicity, or 401(k) for maximum flexibility and higher limits.
• 100+ employees: 401(k) is your primary option.

Consider Your Budget

• Lean years expected? SEP IRA allows you to skip contributions entirely.
• Steady cash flow? SIMPLE IRA's required match is predictable (typically 1–3% of payroll).
• Maximizing personal savings? Solo 401(k) lets you shelter the most income.

Consider Your Employees' Needs

• Want employees to save on their own? 401(k) or SIMPLE IRA allow salary deferrals.
• Prefer to control all contributions? SEP IRA keeps it simple.
• Employees want Roth options? Only the 401(k) currently offers this.

Common Mistakes to Avoid

Starting too late. The earlier you establish a plan, the more tax advantages you accumulate. Plans must generally be set up by the business's tax-filing deadline (including extensions) for the year you want to claim contributions.

Ignoring the equal contribution rule. With a SEP IRA, whatever percentage you contribute for yourself must be contributed for all eligible employees. Forgetting this can lead to compliance issues and penalties.

Overlooking the two-year SIMPLE IRA rule. If an employee withdraws from a SIMPLE IRA within the first two years of participation, the early withdrawal penalty is 25%—not the usual 10%. Make sure employees understand this.

Not reviewing annually. Your business changes, and your retirement plan should too. An owner who starts with a SEP IRA might benefit from switching to a Solo 401(k) as income grows. Review your plan each year during tax planning.

Skipping professional advice. A CPA or financial advisor who specializes in small business retirement plans can identify the optimal structure for your specific situation and help you navigate compliance requirements.

Setting Up Your Plan: Next Steps

1. Evaluate your needs using the criteria above.
2. Choose a plan provider. Banks, brokerages, and specialized retirement plan providers all offer these plans. Compare fees, investment options, and administrative support.
3. Complete the paperwork. SEP and SIMPLE IRAs can be established with a simple form. 401(k) plans require a plan document and may need a third-party administrator.
4. Communicate with employees. Explain the plan benefits, contribution options, and enrollment process.
5. Set calendar reminders for contribution deadlines and annual reviews.

Keep Your Business Finances Organized

As you build a retirement plan for yourself and your team, keeping clean financial records becomes even more critical. Retirement contributions, employer matches, and tax deductions all need to be tracked accurately. Beancount.io provides plain-text accounting that gives you complete transparency and control over your financial data—making it easy to track contributions, verify deductions, and stay compliant. Get started for free and see why business owners are switching to plain-text accounting.