Self-Employment Tax Calculator
Estimate your self-employment (SE) tax liability and the deductible portion you can claim on your federal income tax return.
Formulas Used (IRS Schedule SE, 2024)
1. Net SE Earnings:
SE Earnings = Net Income × 0.9235
2. Social Security Tax:
SS Taxable = min(SE Earnings, max(0, $168,600 − W-2 Wages))
SS Tax = SS Taxable × 12.4%
3. Medicare Tax:
Medicare Tax = SE Earnings × 2.9%
4. Additional Medicare Tax (if applicable):
Combined Income = SE Earnings + W-2 Wages
Add. Medicare Tax = max(0, Combined Income − $200,000) × 0.9%
5. Total SE Tax:
Total SE Tax = SS Tax + Medicare Tax + Additional Medicare Tax
6. Deductible Portion:
Deduction = Total SE Tax × 50%
7. Effective Rate:
Effective Rate = Total SE Tax ÷ Net Income × 100
Assumptions & References
- Based on 2024 tax year figures (IRS Schedule SE).
- The 92.35% factor (1 − 7.65%) accounts for the employer-equivalent deduction before computing SE earnings — per IRS Publication 334.
- Social Security wage base for 2024 is $168,600 (IRS Rev. Proc. 2023-34). Income above this cap is not subject to the 12.4% SS tax.
- Medicare tax (2.9%) applies to all SE earnings with no cap.
- Additional Medicare Tax (0.9%) applies to combined wages and SE income exceeding $200,000 (single) / $250,000 (married filing jointly) — this calculator uses the single-filer threshold. See IRS Form 8959.
- The 50% deductible portion of SE tax is deducted on Schedule 1 (Form 1040), Line 15, reducing adjusted gross income.
- This calculator does not account for state-level taxes, health insurance deductions, or retirement contributions.
- References: IRS Schedule SE, IRS Publication 334, IRS Publication 505, IRC §1401, IRC §1402.