Self-Employment Tax Calculator
Enter your net self-employment earnings to estimate the US self-employment (SECA) tax you owe, broken down into its Social Security and Medicare portions, plus the half you can deduct.
Estimate SECA tax
Net profit from self-employment (business income minus deductible business expenses), before the SE-tax deduction.
Estimated 2024 US SECA tax on $80,000.00 of net earnings.
- Taxable base (92.35%)
- $73,880.00
- Social Security portion (12.4%)
- $9,161.12
- Medicare portion (2.9%)
- $2,142.52
- Deductible half
- $5,651.82
How self-employment tax is calculated
US self-employment tax (SECA) covers the Social Security and Medicare contributions that an employee and employer would otherwise split. First, 92.35% of your net earnings becomes the taxable base. Social Security tax of 12.4% applies to that base up to the annual wage base ($168,600 for 2024); Medicare tax of 2.9% applies to the entire base with no cap. Half of the total is deductible on your income tax return.
Taxable base = Net earnings × 0.9235
Social Security = min(Taxable base, 168,600) × 0.124
Medicare = Taxable base × 0.029
SE tax = Social Security + Medicare
Deductible half = SE tax / 2- Net earnings
- Net profit from self-employment
- Taxable base
- 92.35% of net earnings
- Wage base
- 2024 Social Security cap of $168,600
- Deductible half
- Employer-equivalent portion you may deduct
This models US SECA tax only. Canada has no self-employment tax of this kind; self-employed Canadians instead pay both the employee and employer shares of Canada Pension Plan (CPP) contributions, which are calculated differently and are not covered here.
$80,000 in net self-employment earnings
Suppose your net self-employment earnings are $80,000. The taxable base is 80,000 × 0.9235 = $73,880. Because that is below the $168,600 wage base, the full base is subject to Social Security tax: 73,880 × 0.124 = $9,161.12. Medicare tax is 73,880 × 0.029 = $2,142.52. The self-employment tax owed is 9,161.12 + 2,142.52 = $11,303.64, and the deductible half is $5,651.82.
This is an educational estimate based only on the value you enter. It is not tax advice and does not reflect your full tax situation.
What this calculator assumes
- US SECA tax only, using 2024 rates and the $168,600 Social Security wage base.
- The 0.9% Additional Medicare Tax on high earners and any wages from a separate W-2 job that reduce the Social Security wage base are not modeled.
- Net earnings are treated as already net of deductible business expenses.
- Income tax, state or local taxes, and Canadian CPP contributions are not included.
Self-employment tax FAQ
Why is only 92.35% of my earnings taxed?
The 92.35% factor (equivalently, 100% minus 7.65%) approximates the employer-share deduction that employees effectively receive, so self-employed people are not taxed on the portion an employer would have paid. It is applied before the Social Security and Medicare rates.
Does this apply to self-employed people in Canada?
No. This calculator estimates US self-employment tax only. Self-employed Canadians do not pay SECA tax; instead they contribute both the employee and employer portions of the Canada Pension Plan (CPP), which uses different rates and limits not covered here.
Sources and review notes
- Internal Revenue Service — Self-Employment Tax (Social Security and Medicare Taxes), Schedule SE
- Social Security Administration — Contribution and Benefit Base
Methodology last checked Jul 14, 2026. Formula implementation is covered by deterministic unit tests. No tax professional review is claimed yet.