BizTax by DueKit
Choose your U.S. tax calculator.
Choose the tax question you need, then open the calculator.
Self-employment taxSelf-employment tax calculator
Annual self-employment tax estimate.Estimate federal self-employment tax with a clear breakdown.
Quarterly estimated taxQuarterly estimated tax calculator
Quarterly payment estimate.Estimate equal quarterly payments and a simplified safe harbor reference.
LLC vs S-CorpLLC vs S-Corp calculator
Compare annual LLC vs S-Corp tax.Compare simplified LLC and S-Corp federal tax treatment.
LLC cost by stateLLC cost by state
5-state LLC filing-cost hub.Compare fixed first-year LLC costs across 5 pilot states.
Trust and review path
Review methods, sources, and limits
Review methods, sources, updates, and disclosure detail before you rely on an estimate.
Official sources
Review the IRS and state materials behind each estimate.
Method notes
Review formulas, thresholds, and rounding rules.
Limits and corrections
Check updates, scope limits, and correction paths.
State costs
LLC cost by state
The public comparison flow lives on the state hub. Single-state detail pages stay rehearsal-only while their deeper filing notes and source trails continue to be reviewed.
Current pilot-state coverage
California, Florida, Texas, New York, and Delaware are the current reviewed pilot states. Open the hub for the stable comparison surface, and treat single-state detail routes as rehearsal note sets rather than public landing pages.
What these tools cover
What you can estimate here
Federal calculators stay current first. State-fee coverage stays limited to the five pilot states.
Federal estimates
Use the self-employment tax, quarterly estimated tax, and LLC vs S-Corp calculators with current federal 2025 and 2026 data packages.
State cost comparisons
Use LLC cost by state to compare current 2026 filing fees and annual costs across Delaware, New York, Florida, Texas, and California.