Calculate your SE tax with detailed Social Security, Medicare, and QBI deduction breakdowns. See how W-2 income interacts with the Social Security cap.
Self-employment tax covers both the employer and employee portions of FICA — 12.4% for Social Security and 2.9% for Medicare, totaling 15.3%. However, only 92.35% of your net SE income is subject to this tax, because the IRS accounts for the employer-equivalent portion.
Social Security tax only applies up to a wage cap ($184,500 in 2026). If you also have W-2 income, that income uses up part of the cap first, reducing the Social Security portion of your SE tax. Medicare has no cap, and an additional 0.9% Medicare tax applies to combined income exceeding $200,000.
The QBI deduction (Section 199A) allows qualifying self-employed individuals to deduct up to 20% of their qualified business income. This deduction is taken on your tax return — it reduces your federal income tax, but not your SE tax. The deduction is limited to 20% of your taxable income.
Because self-employed individuals don’t have taxes withheld from paychecks, the IRS requires quarterly estimated payments. Missing these can result in underpayment penalties. The quarterly amount shown here divides your total estimated annual tax by four.