Self-Employed Tax Estimator

How it works

Estimates your 2026 federal income tax, self-employment tax and quarterly payments as a self-employed person. A planning estimate, not tax advice.

1. Net SE profit = Gross self-employment income minus Deductible business expenses, never below zero. SE tax base = 92.35% of net profit.
2. SE tax = 12.4% of the base (capped at the $184,500 2026 wage base minus Other earned income) plus 2.9% of the whole base. Half of SE tax is then deducted.
3. AGI = net profit + other earned income minus half SE tax, retirement contribution and health premium. Taxable income = AGI minus the standard deduction: single or separate $16,100, joint $32,200, head of household $24,150.
4. Federal tax applies the 2026 bracket rates (10% to 37%) for your filing status to taxable income. State tax = (net profit + other income minus retirement) × State tax estimate %.
5. Total = SE tax + federal + state. Each quarter = total ÷ 4 (Apr 15, Jun 15, Sep 15, Jan 15). Weekly = total ÷ 52. After-tax = profit + other income minus total.

Questions

What does the estimate leave out?

Per the page: the QBI deduction, tax credits such as CTC and EITC, depreciation, multi-state returns, and phaseouts on the self-employed health insurance deduction. It uses the standard deduction only. For a binding number, ask a CPA.

I also have a W-2 job. How is that handled?

Other earned income stacks with your business profit in the brackets and uses up part of the Social Security wage base. The total includes tax on that income and does not subtract withholding, so it can overstate what you still owe.

How are the quarterly amounts set?

Four equal parts of the yearly total, labeled Apr 15, Jun 15, Sep 15 and Jan 15. It does not adjust for income that arrives unevenly. Pay quarterly to avoid IRS underpayment penalties, as the page notes.