Self-Employment Tax Breakdown: 92.35% Rule and Social Security Cap
The "hidden" math behind your tax bill can change your liability by thousands. Here is exactly how the IRS determines your self-employment tax base.
The 92.35% Factor
The IRS only taxes 92.35% of your net profit from business. Why? Because as a self-employed person, you get a "deduction" for the employer-equivalent portion of your self-employment tax. This factor effectively reduces your tax base by 7.65%.
| Metric | Description | 2025 Value | 2026 Estimate |
|---|---|---|---|
| SE Combined Rate | Social Security (12.4%) + Medicare (2.9%) | 15.3% | 15.3% |
| 92.35% Rule | Percentage of net profit subject to SE tax | 92.35% | 92.35% |
| SS Wage Base Cap | Maximum earnings subject to SS portion | $176,100 | $184,500 |
| Addl. Medicare | Surcharge for high earners (> $200k/$250k) | 0.9% | 0.9% |
How to Calculate Your Effective Rate
If your net profit is below the Social Security cap, your effective tax rate on your actual profit is approximately 14.13% (which is 15.3% of 92.35%).
Step 1
Take your Gross Income and subtract all Business Expenses to find your Net Profit.
Step 2
Multiply your Net Profit by 0.9235. This is your taxable base.
Step 3
Multiply that base by 0.153 to find your total SE tax liability (up to the cap).