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Estimated tax safe harbor calculator (2026)

Self-employed, or have income without withholding? See the least you must pay in estimated tax and withholding for 2026 to avoid the underpayment penalty, each quarter's installment, and what's left to pay by January 15, 2027.

✓ TestedMatches the IRS example in Publication 505 (2026)
Still to pay by January 15, 2027–

The rule (IRS Publication 505, 2026): no penalty if you owe less than $1,000 after withholding, or if withholding and estimated payments cover the smaller of 90% of your 2026 tax and 100% of your 2025 tax (110% if your 2025 AGI was over $150,000, or $75,000 married filing separately). Farmers and fishers: 66⅔% of 2026 tax, and the 110% rule doesn't apply. Without a full-year 2025 return, only the 90% test applies. Estimated payments are due in four equal parts: April 15, June 15, September 15, 2026 and January 15, 2027. Paying late quarters in full stops the penalty from growing, but earlier short quarters can still owe a little; withholding counts as paid evenly through the year, so raising withholding late in the year helps more. Total tax is the tax on your return, including self-employment tax, before withholding and payments.

How it works

You avoid the penalty if withholding plus estimated payments reach the smaller of 90% of your 2026 tax and 100% of your 2025 tax, or 110% if your 2025 AGI was over $150,000 ($75,000 married filing separately), or if you owe less than $1,000. The calculator takes the smaller, subtracts withholding, splits the rest into four installments and shows what's left after what you've paid. It gives the same answer as the example in IRS Publication 505 (2026): 110% of $42,581, $46,839, is less than 90% of $71,253. More in the safe harbor guide.

Worked examples