Small Business Tax Tool

SEP IRA Calculator
+ Solo 401k Comparison

Use this SEP IRA Calculator to Calculate your SEP IRA contribution and see how it compares to a Solo 401k.

How is a SEP IRA Contribution Calculated?

Using a SEP IRA calculator helps self-employed individuals estimate their maximum contribution and compare it with other retirement options like a Solo 401k.

For sole proprietors and single-member LLCs, your maximum SEP IRA contribution is limited by the “20% Rule”. You must deduct half of your self-employment tax to find your Adjusted Net Earnings, and your maximum limit is strictly 20% of that number.

SEP IRA vs Solo 401k: Which Is Better?

While a SEP IRA is simple to set up, a Solo 401k often allows significantly higher contributions because it includes both employee and employer limits.

  • SEP IRA: Limited to ~20% of your net self-employment income.
  • Solo 401k: Allows both employee deferral + employer contribution.
  • Result: The Solo 401k usually wins for freelancers and consultants looking to maximize tax savings.
Your self-employment income before taxes
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Determines limits (Catch-ups don’t apply to SEP)
βš™οΈ Advanced IRS Limits (Fully Editable)
These fields default to 2025 IRS limits. You can edit them manually if tax laws change.
$
$
$
$
$
$
βœ… The Solo 401k Allows Higher Contributions
Maximum SEP IRA Contribution Limit
$0

Solo 401k Advantage: $0 more contribution potential

(Based on the strict 20% Employer Rule)
SEP IRA Max
$0
Employer Contribution Only
Solo 401k Max
$0
Employee + Employer Total
Self-Employment Tax Estimate$0
Adjusted Net Earnings (Base for Math)$0
SOLO 401k ADVANTAGE BREAKDOWN
1. Employee Deferral Limit (Not allowed in SEP)$0
2. Employer Profit Sharing Limit (Same as SEP)$0
Total Solo 401k Allowed$0
Disclaimer: This calculator is for educational purposes only. Tax laws are subject to change. Please consult a licensed CPA or tax professional before making financial, business, or retirement decisions.
πŸ“… Updated for 2025/2026 IRS Tax Guidelines

Why You Need a SEP IRA Calculator

A reliable SEP IRA calculator is arguably the most important tax-planning tool a self-employed individual can use today. In fact, if you are a freelancer, consultant, or small business owner, understanding exactly how much you can contribute to your retirement account is absolutely essential for reducing your taxable income.

πŸ’‘ Did you know? Most self-employed individuals actually under-contribute to their SEP IRA by thousands of dollars each year because the IRS self-employment tax math is extremely confusing. Fortunately, our calculator ensures you safely maximize your tax deductions.

Avoiding Excise Tax Penalties

Furthermore, because the IRS rules surrounding self-employment taxes require a complex circular formula, you cannot simply guess your contribution limits. Consequently, using a dedicated SEP IRA contribution calculator ensures you do not accidentally trigger excise tax penalties by over-contributing to your account.

How to Use This SEP IRA Calculator Effectively

Using this SEP IRA calculator is incredibly straightforward. In fact, it takes less than 30 seconds to reveal your maximum IRS limit. Simply follow the steps below to find your exact tax shelter potential.

Step-by-Step Instructions

  • First, enter your net business profit: Input your Schedule C self-employment income before taxes.
  • Next, select your age: While age-based catch-up limits do not apply to a SEP IRA, we use this data to accurately compare your results against alternative accounts.
  • Review the estimated SE tax: The calculator automatically determines and deducts half of your self-employment tax behind the scenes.
  • Finally, view your maximum contribution: Ultimately, you get a penny-perfect cap that you can hand directly to your CPA.

How the 20% SEP IRA Rule Actually Works

Many business owners mistakenly believe they can contribute a flat 25% of their revenue into a SEP IRA. However, if you operate as a sole proprietor or a single-member LLC, the IRS views you much differently than a large S-Corp paying W-2 wages.

Understanding Adjusted Net Earnings

Therefore, you must calculate your retirement limit based entirely on your Adjusted Net Earnings. According to official IRS guidelines, you must first subtract half of your self-employment tax, as well as the SEP contribution itself, from your net profit.

Ultimately, this circular mathematical formula results in an effective maximum contribution limit of 20%. Because running this formula by hand is incredibly tedious, our self employed retirement calculator automates the entire process for you. Specifically, it factors in the current Social Security wage base and Medicare taxes to give you an accurate IRS limit.

SEP IRA for Freelancers, LLCs, and Small Business Owners

Whether you are a 1099 independent contractor, a gig worker, or running a single-member LLC, a SEP IRA is undeniably one of the most powerful wealth-building tools available. Because it requires virtually no administrative setup and zero annual IRS reporting, it serves as the ultimate “set it and forget it” tax shelter.

The Hidden Trap with W-2 Employees

On the other hand, if you plan to scale your business and hire W-2 employees, you must be extremely careful. By law, whatever percentage of profit you contribute to your own account, you must also contribute to eligible employees’ accounts out of your own pocket.

For instance, if you contribute 20% to your own SEP IRA, and you have an employee making $50,000 a year, you must deposit $10,000 into their retirement account. Consequently, this is exactly why utilizing a SEP IRA calculator is vital for mapping out your long-term business strategy before you hire staff.

Real Example: $100,000 Income Breakdown

To illustrate exactly how this tool works in the real world, let’s assume you earn exactly $100,000 in net self-employment income this year. Here is how your maximum SEP IRA contribution breaks down behind the scenes.

The Step-by-Step Tax Math

  1. Calculate Self-Employment Tax: First, you owe 15.3% on 92.35% of your earnings. Your total SE tax is roughly $14,130.
  2. Deduct Half SE Tax: Next, the IRS allows you to deduct half of that SE tax ($7,065) from your net profit.
  3. Find Adjusted Net Earnings: Consequently, your new base for calculating retirement drops to ~$92,935.
  4. Apply the 20% Rule: Finally, multiply that adjusted base by 20%.

The Final Result: Your maximum allowed SEP IRA contribution is ~$18,587. For instance, if you were in the 24% federal tax bracket, making this exact contribution would immediately save you over $4,400 in income taxes for the year.

SEP IRA vs Solo 401k: Which Is Better?

While a SEP IRA is wonderfully simple to manage, you might be wondering why our calculator also outputs a second number. We purposely built this to double as a dynamic Solo 401k vs SEP IRA comparison tool so you never leave money on the table.

Why the Solo 401k Usually Wins for Tax Savings

In reality, a Solo 401k often allows for significantly higher contributions. This happens because a Solo 401k legally recognizes you as both the employee and the employer. Because of this unique structure, you can double-dip your tax deductions. You can use our dedicated Solo 401k calculator to see exactly how those massive employee deferrals work.

When the SEP IRA Remains the Best Choice

Despite the higher limits of a Solo 401k, a SEP IRA is still better for certain business owners. For example, if your net self-employment income exceeds $350,000, 20% of your profit will easily max out the $70,000 IRS limit. At that income tier, the Solo 401k loses its advantage, making the simpler SEP IRA the obvious choice.

Tax Deadlines and IRS Reporting

Another major benefit of the SEP IRA is the incredibly flexible funding deadline. Unlike traditional 401k accounts that require employee deferrals to be made by December 31st, a SEP IRA gives you much more breathing room.

When Do You Have to Fund the Account?

Specifically, you have until your tax filing deadline (including extensions) to open and fund the account. As a result, you can wait until your CPA finishes your tax return in September to decide exactly how much cash you want to contribute for the previous tax year.

πŸš€ Take Control of Your Financial Future

Don’t stop at retirement planning. Use our suite of free, professional-grade financial calculators to manage your taxes, optimize your debt, and calculate your true take-home pay.

Frequently Asked Questions

Common SEP IRA Questions

What is the SEP IRA contribution limit for 2025?
For 2025, the absolute maximum contribution limit is $70,000, or up to 25% of compensation. However, for sole proprietors, this equates to roughly 20% of adjusted net earnings. Furthermore, this limit is adjusted periodically by the IRS to account for inflation.
Is a SEP IRA better than a Solo 401k?
Ultimately, a SEP IRA is infinitely simpler to set up and administer. However, a Solo 401k usually allows for much higher contributions for most self-employed individuals because it permits both employee salary deferrals and employer profit-sharing.
Can I contribute to both a SEP IRA and a Solo 401k?
Yes, technically you can maintain both accounts. Nevertheless, your total combined employer contributions across all plans cannot exceed the IRS maximum limits, meaning maintaining both accounts is usually redundant for a single business.
Are SEP IRA contributions fully tax-deductible?
Yes, absolutely. Every dollar you contribute to your SEP IRA (up to your legal limit) directly reduces your taxable business income for the year. Consequently, this saves you money on both federal and state income taxes.
Do I have to contribute to my SEP IRA every year?
No, you do not. Contributions are completely discretionary. In fact, you can max out your account during highly profitable years and contribute absolutely nothing during slower years without facing any IRS penalty.
Disclaimer: This SEP IRA calculator and financial guide provide estimates based on current IRS guidelines for educational purposes only. Tax laws are consistently subject to change. Always consult a qualified CPA, financial advisor, or tax professional for personalized advice before making retirement contributions.

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