Self-Employment Tax Calculator Formula

Understand the math behind the self-employment tax calculator. Each variable explained with a worked example.

Use the Self-Employment Tax Calculator

Formulas Used

Self-Employment Tax

se_tax = min(taxable_se, 168600) * 0.124 + taxable_se * 0.029

Social Security (12.4%)

ss_portion = min(taxable_se, 168600) * 0.124

Medicare (2.9%)

medicare_portion = taxable_se * 0.029

Deductible Half

deductible_half = (min(taxable_se, 168600) * 0.124 + taxable_se * 0.029) / 2

Variables

VariableDescriptionDefault
net_earningsNet Self-Employment Income(USD)80000
taxable_seDerived value= net_earnings * 0.9235calculated

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%

  • Social Security: 12.4% (up to $168,600 in 2024)
  • Medicare: 2.9% (no cap)
  • Additional Medicare: 0.9% on earnings over $200,000

    • You can deduct half of SE tax from your adjusted gross income.

    Worked Example

    $80,000 net self-employment income.

    net_earnings = 80000
    1. 01Taxable base = $80,000 x 92.35% = $73,880
    2. 02SS = $73,880 x 12.4% = $9,161
    3. 03Medicare = $73,880 x 2.9% = $2,143
    4. 04Total SE tax = $11,304
    5. 05Deductible half = $5,652

    Ready to run the numbers?

    Open Self-Employment Tax Calculator