Why self-employment tax uses 92.35% of net profit

The 92.35% factor defines regular-method net earnings

IRS Publication 505's 2026 self-employment worksheet multiplies expected self-employment profit by 92.35%. If the result is below $400 under that worksheet, it does not proceed to the regular SE-tax amount. This factor is not a business-expense estimate and should not be applied to gross receipts before actual expenses are considered.

For a $60,000 net profit, the regular base is $55,410. That is the number used for the basic Social Security and Medicare component steps in the simplified example.

Social Security and Medicare do not share every limit

The Social Security component is 12.4% up to the available contribution-and-benefit base. W-2 Social Security wages use that base first, so entering wages matters. The regular Medicare component is 2.9% without the same wage-base cap. Additional Medicare Tax can apply above filing-status thresholds after combining relevant wages and self-employment income.

For 2026, the published Social Security contribution base is $184,500. A calculator should state the year because this amount changes.

• SE-tax base: net profit × 92.35%.
• Social Security component: 12.4% within remaining wage-base room.
• Regular Medicare component: 2.9% of the SE-tax base.

The half-SE-tax deduction lives outside the SE-tax formula

The expected employer-equivalent-half deduction is generally one-half of the regular SE-tax amount in the Publication 505 workflow. It is used as an adjustment when estimating AGI. It does not cut the SE-tax bill in half and it does not replace business expenses.

Special farm and nonfarm optional methods, multiple businesses, losses, church employee income, partnerships, and international social-security agreements can require a fuller Schedule SE analysis.