Privacy and important limitations
QuarterlyTaxCheck is a public educational tool. Review these notes before relying on any result.
Privacy
QuarterlyTaxCheck runs as a lightweight public calculator. Do not enter sensitive information you would not want exposed in a normal browser session. Avoid entering Social Security numbers, taxpayer IDs, or full tax-return details.
This project is designed for planning guidance only and should be used with caution on shared or public devices.
Disclaimer
QuarterlyTaxCheck does not provide tax advice, legal advice, accounting advice, or a guarantee of penalty avoidance. It does not prepare or file tax returns.
The tool uses simplified assumptions, including a prior-year safe-harbor baseline and a rough self-employment tax preview. Real outcomes can differ based on credits, deductions, timing, annualized-income methods, multiple income streams, payroll, entity structure, and state tax rules.
Best use
Use this tool to sanity-check whether you appear roughly on track before the next federal estimated-tax deadline. If your situation is complex or high-value, review the output with a qualified tax professional.