How the 2026 estimate works
The calculator follows the IRS 2026 estimated self-employment tax worksheet: 92.35% of net profit becomes net earnings, the Social Security portion is limited by the $184,500 combined wage base, and Medicare applies without that wage cap. Half of regular self-employment tax is deducted when estimating adjusted gross income.
Net earnings = Net profit × 92.35%
SE tax = Social Security portion + Medicare portion
Taxable income = AGI − standard deduction − entered QBI deduction
Official 2026 sources
- IRS Internal Revenue Bulletin 2025-45 — 2026 brackets and standard deductions.
- IRS Publication 505 (2026) — estimated-tax and self-employment worksheets.
- Social Security Administration contribution and benefit base — 2026 taxable maximum.
What this estimate excludes
- Tax credits, itemized deductions, capital gains rates, alternative minimum tax, net investment income tax, and state or local taxes.
- Automatic QBI, retirement-plan, health-insurance, home-office, depreciation, or business-expense eligibility calculations.
- Special Schedule SE methods, multiple self-employed spouses, church income, farm optional methods, fiscal-year rules, or nonresident tax treatment.
- Estimated-payment safe harbors, withholding already paid, penalties, and payment scheduling.
Frequently asked questions
What is self-employment tax?
Self-employment tax generally covers Social Security and Medicare taxes for people who work for themselves. It is separate from federal income tax.
Why is only 92.35% of profit used?
The 2026 IRS estimated-tax worksheet multiplies expected self-employment income by 92.35% to determine net earnings for the self-employment tax calculation.
Does this calculate the QBI deduction?
No. Qualified business income eligibility and limitations can be complex. The calculator accepts a QBI deduction amount only when you have determined it separately.
Is the quarterly amount what I must pay?
Not necessarily. It is one-fourth of the estimated annual total and does not apply prior-year safe harbors, withholding, payment dates, or annualized-income rules.