2026 small business tax estimator

Rough federal figures for US owners of sole proprietorships and single-member LLCs: what to set aside each quarter, your self-employment tax, and whether an S-corp might save you money.

Estimate only, not tax advice. These tools use 2026 federal rates with simplified assumptions. They leave out state and local tax, credits, itemized deductions, retirement contributions, health insurance and many other items that change your real bill. Cypher is not a CPA firm and does not prepare tax returns or give tax advice. Always confirm with your CPA or tax preparer before you pay or change anything.

Filing status

Expected 2026 net business profitBusiness income minus business expenses (Schedule C line 31)

Other wages (W-2) in 2026Yours, plus your spouse's if filing jointly. 0 if none.

Federal tax withheld from those wagesFrom pay stubs, for the full year

Estimated payments already made for 2026

Estimated payment per remaining quarter

2026 estimated tax due dates

April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027. Paying at least 100% of last year's total tax (110% if last year's income was over $150,000) in four equal parts usually avoids an underpayment penalty, even if this year's bill turns out higher. Your CPA can tell you which approach is safer for you.

How these estimates work

2026 federal income tax brackets and standard deduction ($16,100 single, $32,200 married filing jointly) from the IRS 2026 inflation adjustments.
Self-employment tax: 15.3% on 92.35% of net profit; the 12.4% Social Security part stops at the 2026 wage base of $184,500 (reduced by your W-2 wages); 2.9% Medicare has no cap. Additional Medicare tax of 0.9% applies above $200,000 (single) or $250,000 (joint).
Half of self-employment tax is deducted before income tax. A simplified 20% qualified business income deduction is included only below the 2026 threshold ($201,750 single, $403,500 joint); above it we leave it out, which may overstate your tax.
Not included: state and local taxes, credits, itemized deductions, retirement contributions, health insurance, capital gains, other income types, and penalties.

Sources: 2026 inflation adjustments (Journal of Accountancy, IRS Rev. Proc. 2025-32) · 2026 Social Security wage base (American Payroll Association). Figures checked October 2026.

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Estimates are only as good as the books behind them. We keep your books closed by business day 5, so you and your CPA always know your real profit. From $149 a month.

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