Quarterly estimated tax calculator (2026)
Pay at least the smaller of 90% of your 2026 tax or 100% of your 2025 tax (110% if your 2025 adjusted gross income was over $150,000) through withholding and four estimated payments: April 15, June 15 and September 15, 2026, and January 15, 2027.
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Informational estimate, not tax advice. SuperBooks does not prepare or file tax forms.
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The formula
Safe harbor = the smaller of 90% × expected 2026 tax and 100% × 2025 tax (110% when 2025 AGI was over $150,000, or $75,000 married filing separately). Estimated tax to pay = safe harbor − withholding, in four equal payments; none is required if you expect to owe less than $1,000 after withholding and refundable credits.
Sources
Last checked 21 October 2026.
Run it with curl
curl "https://app.superbooks.io/api/tools/estimated-tax?expectedTax=18000&priorYearTax=15000&priorYearAgi=90000"Questions
- When are 2026 estimated tax payments due?
- April 15, 2026, June 15, 2026, September 15, 2026 and January 15, 2027. If a date falls on a Saturday, Sunday or legal holiday, a payment made the next day that is not one is on time.
- Who has to pay estimated tax for 2026?
- In most cases, you do if you expect to owe at least $1,000 for 2026 after withholding and refundable credits, and you expect your withholding and refundable credits to be less than the smaller of 90% of your 2026 tax or 100% of your 2025 tax.
- When does the 110% rule apply?
- When your 2025 adjusted gross income was more than $150,000, or more than $75,000 if your filing status for 2026 is married filing separately. Then 110% of your 2025 tax replaces 100%.