How this calculator works
Tax year: 2026, United States. Self-employed people pay both halves of Social Security and Medicare through Schedule SE. Net earnings are multiplied by 92.35% to arrive at the taxable base, which reflects the employer-half deduction. Social Security is 12.4% of that base up to the $184,500 wage base. Medicare is 2.9% of the whole base. The additional Medicare tax is 0.9% of the base above $200,000 for single and head-of-household filers, $250,000 for joint filers and $125,000 for married filing separately. Half of the Social Security and Medicare portions is deductible against income tax; the additional Medicare tax is not part of that deduction. The model leaves out income tax, wages from a job that also count toward the wage base and the additional Medicare threshold, church-employee rules, and state tax.
Formula
Earnings subject to SE tax = 92.35% x net earnings. Social Security = 12.4% x min(base, 184,500). Medicare = 2.9% x base. Additional Medicare = 0.9% x max(0, base - status threshold). Total = the three parts. Deductible half = 50% x (Social Security + Medicare).
Worked example
Net earnings of $80,000 give a base of $73,880. Social Security is $9,161.12, Medicare is $2,142.52 and no additional Medicare tax applies, so the total is $11,303.64. Half of that, $5,651.82, is deductible against income tax.
Frequently asked questions
Why is only 92.35% of my earnings taxed?
The law treats self-employed people as both employee and employer. Multiplying by 92.35% removes the employer half before applying the rates, which achieves the same result as deducting that half first, and it is the figure Schedule SE uses.
Does this include federal income tax?
No. Self-employment tax is separate from income tax. Your income tax depends on the standard or itemised deduction, credits and other income, and is calculated on a different return line.
What if I also have a job?
Wages from a job count toward the Social Security wage base and the additional Medicare threshold before self-employment income is added. This calculator assumes self-employment is the only earned income, so it can overstate the Social Security portion and the additional tax when you also have wages.
Is the whole tax deductible?
No. Half of the Social Security and Medicare portions is deductible against income tax. The additional 0.9% Medicare tax gives no deduction.