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The figures this uses
| Figure | 2026 | Source |
|---|---|---|
| Estimated tax | generally required if you expect to owe $1,000 or more. Safe harbour: 90% of the current year's tax or 100% of the prior year's, whichever is smaller | irs.gov |
| Estimated tax safe harbour, higher income | 110% of the prior year's tax when prior-year AGI was over $150,000 ($75,000 if married filing separately) and less than two-thirds of income is from farming or fishing | irs.gov |
| Estimated tax payment periods | Jan 1-Mar 31 due April 15 · Apr 1-May 31 due June 15 · Jun 1-Aug 31 due September 15 · Sep 1-Dec 31 due January 15. The penalty is figured separately for each period | irs.gov |
This calculator is for educational purposes only and does not constitute tax, legal, or financial advice. It covers United States federal tax and simplifies in the ways noted beside each result. Consult a qualified tax professional about your situation.