What this tool tells you
This planning estimate is for a U.S. sole proprietor or single-member LLC taxed as a disregarded entity. It uses 2026 federal brackets, status-based standard deductions, a simplified Schedule SE calculation, and the stated Social Security wage base.
How the math works
The model includes regular self-employment Social Security and Medicare tax, an Additional Medicare Tax estimate, the deduction for half of regular self-employment tax, and progressive ordinary-income brackets. It does not model state/local tax, QBI, credits, itemized deductions beyond the entered amount, capital gains, AMT, or every household circumstance.
Frequently asked questions
Does this calculate quarterly estimated-tax safe harbor?
No. It estimates annual federal tax from entered assumptions and subtracts withholding/payments. Required installments depend on prior-year tax, withholding timing, current income, and other rules; consult Form 1040-ES and Publication 505.
Can an S corporation or partnership use it?
No. This simplified model is limited to one sole proprietor or single-member LLC taxed as a disregarded entity. Entity-level and owner-compensation rules require different calculations.
Official sources
- IRS: 2026 Form 1040-ES
Estimated-tax worksheets, safe-harbor tests, due dates, and payment instructions.
- IRS: 2026 tax brackets and inflation adjustments
2026 federal income-tax bracket thresholds.
- IRS Topic 554: Self-employment tax
Self-employment and Additional Medicare Tax overview.
- IRS Publication 505
Withholding, estimated tax, and annualized installment rules.
Educational planning information only—not tax, legal, accounting, or financial advice. Fees and tax rules can change; verify current terms with the provider or official authority.