Self-Employment Tax Calculator

Fixed reference tax year 2026, generally filed in 2027. Assumes one ordinary sole-proprietor business, no other income or W-2 wages, and zero modeled spouse income. Basic standard deduction assumes under age 65, not blind and not a dependent; eligibility is not determined. Shared IRS 2026 rate schedules use the selected single or joint filing status.

Signed business profit/loss equals gross income less entered eligible expenses. Loss tax benefits and carryforwards are not modeled. The regular SE method uses exact 92.35% of positive profit; the $400 net-earnings threshold is tested before display rounding. A displayed $400.00 base can therefore be slightly below the exact threshold. Social Security is 12.4% up to the 2026 $184,500 one-person base; Medicare is 2.9% without a cap. Separate Additional Medicare is 0.9% above $200,000 single or $250,000 joint, with no modeled wages.

Each tax component rounds half-up to USD cents from the unrounded SE base. Regular SE tax is rounded Social Security plus base Medicare; its deductible half rounds half-up cents and excludes Additional Medicare. Ordinary taxable income subtracts this deduction and the base standard deduction. QBI deduction, credits, itemization, retirement/health deductions, age additions, other income, optional/church/farm methods, spouse wages, NIIT and state/local tax are excluded. This is a rate-schedule estimate, not the IRS Tax Table or whole-dollar filed-return method.

Four amounts are equal planning portions allocated from cumulative quarters of the included annual estimate, so displayed cents sum to that estimate. The general 2026 Form 1040-ES reference dates are not a determination of required installments. Safe harbors, prior-year tax, withholding, annualization, penalties, disaster relief, filing exceptions and actual timing are not modeled. Annual payments entered reduce only the aggregate estimate and are never assigned to a specific portion; excess entered payments are not a promised refund.