Self-Employment Tax Calculator Formula
Understand the math behind the self-employment tax calculator. Each variable explained with a worked example.
Formulas Used
Self-Employment Tax
se_tax = min(taxable_se, 168600) * 0.124 + taxable_se * 0.029Social Security (12.4%)
ss_portion = min(taxable_se, 168600) * 0.124Medicare (2.9%)
medicare_portion = taxable_se * 0.029Deductible Half
deductible_half = (min(taxable_se, 168600) * 0.124 + taxable_se * 0.029) / 2Variables
| Variable | Description | Default |
|---|---|---|
net_earnings | Net Self-Employment Income(USD) | 80000 |
taxable_se | Derived value= net_earnings * 0.9235 | calculated |
How It Works
Self-Employment Tax
Self-employed individuals pay both the employer and employee portions of FICA taxes.
SE Tax = 92.35% of Net Earnings x 15.3%
You can deduct half of SE tax from your adjusted gross income.
Worked Example
$80,000 net self-employment income.
- 01Taxable base = $80,000 x 92.35% = $73,880
- 02SS = $73,880 x 12.4% = $9,161
- 03Medicare = $73,880 x 2.9% = $2,143
- 04Total SE tax = $11,304
- 05Deductible half = $5,652
Frequently Asked Questions
Why do self-employed people pay more?
Employees split FICA 50/50 with their employer. Self-employed people pay both halves (15.3% total vs 7.65% as an employee). However, the employer half is tax-deductible.
Why is it calculated on 92.35%?
The 92.35% factor (100% - 7.65%) adjusts for the fact that employees do not pay FICA on the employer portion. This prevents double-taxation.
Do I owe SE tax on all income?
SE tax applies to net earnings from self-employment (Schedule C or partnership income). It does not apply to W-2 wages, investment income, or rental income.
Ready to run the numbers?
Open Self-Employment Tax Calculator