Contractor SEP-IRA Contributions: Maximize Retirement Savings

Quick Answer

Contractors can contribute up to 20% of net self-employment income (after the SE tax deduction) to a SEP-IRA, capped at $69,000 annually in 2026. The formula is: (Net Profit × 92.35% × 20%) = Max SEP contribution. For a contractor earning $150,000 net profit, the maximum SEP-IRA contribution is roughly $27,705. This reduces taxable income dollar-for-dollar and saves substantial self-employment taxes.

SEP-IRA Formula for Contractors

Step 1: Calculate net profit (gross income – business expenses).

Step 2: Adjust for self-employment tax deduction (multiply by 92.35%).

Step 3: Apply 20% contribution percentage.

Formula: Net Profit × 0.9235 × 0.20 = Maximum SEP-IRA Contribution

Step-by-step example: Contractor with $120,000 gross income, $30,000 business expenses.

1. Net profit: $120,000 – $30,000 = $90,000
2. Adjusted for SE tax: $90,000 × 0.9235 = $83,115
3. SEP contribution: $83,115 × 0.20 = $16,623

The contractor can contribute $16,623 to a SEP-IRA, reducing taxable income by $16,623.

Example with higher income: Contractor with $400,000 net profit.

1. Net profit: $400,000
2. Adjusted: $400,000 × 0.9235 = $369,400
3. Contribution: $369,400 × 0.20 = $73,880
4. But capped at $69,000 (annual limit)
5. Maximum SEP-IRA contribution: $69,000

Once net profit exceeds roughly $345,000, the $69,000 cap becomes binding.

Tax Savings From SEP-IRA Contributions

A SEP-IRA contribution reduces both income tax and self-employment tax:

Example: Contractor earning $100,000 net profit, 22% tax bracket.

• SEP-IRA contribution: $18,470 (using the formula above)
• Income tax saved: $18,470 × 22% = $4,063
• Self-employment tax savings: $18,470 × 15.3% × 0.9235 = $2,620
• Total tax saved: $6,683

That's 36% of the contribution amount returned as tax savings. The contractor contributes $18,470 and saves $6,683, netting only $11,787 out-of-pocket.

Timing of Contributions

Contractors can contribute to a SEP-IRA for a tax year up to the tax return deadline:

• No extension: April 15 (April 17 if April 15 falls on a weekend)
• With extension: October 15

This flexibility lets contractors wait until mid-year to see their actual net profit, then contribute strategically.

Scenario: Contractor has volatile income. By September, they've earned $80,000 net profit. They estimate year-end profit at $120,000.

• If they contribute $22,164 (20% of $110,700 adjusted) in September and year-end profit is only $100,000, they've over-contributed by $2,000+.
• Better to wait until tax filing (October 15 with extension) to calculate final net profit, then contribute $18,470 (correct amount).

Coordination With Solo 401(k)

Contractors can have either a SEP-IRA or a Solo 401(k), not both (for the same self-employment income in the same year).

Which is better?

SEP-IRA advantage: Simpler, lower contribution limits ($69,000 cap) but easier to administer.

Solo 401(k) advantage: Employee deferrals ($23,500 in 2026) in addition to employer contributions, higher total limits ($69,000 combined), Roth option, loans permitted.

For contractors earning under $120,000, the SEP-IRA is simpler and sufficient. For those earning $150,000+, a Solo 401(k) offers higher contributions (employee deferral + employer contribution), making it more attractive.

Pro-Rata Rule and Contractor IRAs

If a contractor has a traditional IRA (outside the SEP-IRA) with pre-tax money, the pro-rata rule affects Roth conversions but not SEP-IRA contributions.

SEP contributions are separate from traditional IRA balances. A contractor can:

• Have a traditional IRA balance of $50,000.
• Contribute $18,470 to a SEP-IRA.
• Both accounts exist simultaneously without triggering pro-rata issues on the SEP contribution.

However, the pro-rata rule does apply if the contractor later tries a backdoor Roth (contributing to traditional IRA and converting to Roth). The aggregate of the traditional IRA ($50,000) and any new non-deductible contribution ($7,000) makes the conversion partly taxable.

To avoid this, contractors should roll traditional IRAs into a Solo 401(k) (if available) before attempting backdoor Roths.

Multi-Business Contractors

A contractor with multiple businesses (e.g., freelance design and consulting) has separate net profits. The SEP-IRA contribution is based on total net self-employment income from all sources.

Example: Designer earning $60,000 from design, $40,000 from consulting (total $100,000).

• Adjusted for SE: $100,000 × 0.9235 = $92,350
• SEP contribution: $92,350 × 0.20 = $18,470

The $18,470 is the max contribution regardless of how it's split between businesses.

Contractors With Employee IRAs

If a contractor hires employees, the SEP-IRA rules change. The contractor must contribute the same percentage for each eligible employee as for themselves.

Example: Contractor earning $100,000 (after deferring to SEP) and an employee earning $50,000.

• Contractor contribution: $18,470 (20% of adjusted $92,350)
• Percentage: $18,470 / $92,350 = 20%
• Employee must receive: $50,000 × 20% = $10,000 to their SEP-IRA

The contractor must fund the employee's SEP contribution, increasing payroll costs. This is why many contractors switch to Solo 401(k)s or other plans if they hire employees.

Record-Keeping and Documentation

Maintain:

1. Plan document: The SEP-IRA plan agreement (provided by the custodian).
2. Contribution records: Receipt from the custodian showing the contribution amount and date.
3. Tax return Form 5498-SA: Shows the SEP-IRA contribution reported to the IRS.

The custodian (Fidelity, Vanguard, etc.) files Form 5498-SA with the IRS. The contractor reports the contribution on Schedule 1 (Form 1040) and Schedule C (business profit).

Adjusting Contributions: Catch-Up at 50+

Age 50+? You get a catch-up contribution of $7,500 additional (standard IRA catch-up).

However, SEP-IRAs don't have a separate catch-up limit—the 20% calculation is the same. But a Solo 401(k) at age 50+ allows the $7,500 catch-up, making it more attractive if you want maximum contributions.

Comparison for a 50+ contractor earning $150,000 net profit:

• SEP-IRA max: $27,705 (no catch-up available)
• Solo 401(k) max: $23,500 employee deferral + $27,705 employer contribution + $7,500 catch-up = $58,705

The Solo 401(k) wins by $30,000.

Tax Deadlines and Extension Impact

If you file a tax extension (Form 4868), your SEP-IRA contribution deadline extends to October 15.

Scenario: You want to reduce 2025 taxes but filed an extension in April 2025.

• You can contribute to your 2024 SEP-IRA until October 15, 2025.
• You can contribute to your 2025 SEP-IRA until October 15, 2026 (when you file your extension-filed 2025 return).

This flexibility lets you time contributions strategically across years.

Self-Employment Tax Deduction

The SEP contribution itself reduces income tax but not self-employment tax (SE tax is calculated on net profit before the SEP deduction, with only 50% of SE tax deductible above-the-line).

However, the 50% SE tax deduction (calculated separately) does reduce AGI, providing an additional tax reduction.

Full tax impact of an $18,470 SEP contribution:

1. Income tax reduction: $18,470 × 22% = $4,063
2. SE tax impact: $18,470 × 15.3% = $2,829 (SE tax created by the profit)
3. SE tax deduction (50%): $2,829 × 50% × 22% = $311 additional income tax savings
4. Total tax savings: ~$4,374 (roughly 23.7% of contribution)

Mistakes to Avoid

1. Over-contributing: Calculating 20% of gross income instead of net profit. This results in over-contribution and penalties.

2. Missing the deadline: Forgetting the October 15 deadline if you file an extension. The contribution is no longer deductible after October 15.

3. Not adjusting for SE tax: Using net profit directly (not multiplied by 92.35%) inflates the contribution limit.

4. Mixing with Solo 401(k): You cannot have both a SEP-IRA and Solo 401(k) for the same self-employment income in the same year.

5. Ignoring employees: If you hire anyone, the SEP contribution percentage applies to them too, increasing costs.

Sources

• Internal Revenue Service. "SEP-IRA Contribution Limits." IRS.gov.
• Internal Revenue Service. Publication 560: Retirement Plans for Small Business.
• Internal Revenue Service. Form 5498-SA: IRA Contribution Information.
• SBA. "Retirement Plans for Self-Employed." SBA.gov.