Estimated Tax Safe Harbor Calculator (2026)
Find the 2026 estimated tax payments that generally keep you clear of the IRS underpayment penalty: the smaller of 90% of this year’s tax or 100% (110% for higher earners) of last year’s. Includes the 2026 due dates.
Next payment
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2026 due dates · cumulative target
Assumes equal installments and withholding spread evenly across the year. Uneven income? The annualized method (Form 2210, Schedule AI) may lower early payments.
How we calculate
- Prior-year rule = 100% of your 2025 total tax, or 110% if 2025 adjusted gross income was over $150,000 ($75,000 married filing separately).
- Current-year rule = 90% of your expected 2026 total tax.
- Safe-harbor annual payment = the smaller of the two. Paying at least this through withholding and on-time estimated payments generally avoids the underpayment penalty.
- Each 2026 due date (Apr 15, Jun 15, Sep 15, Jan 15 2027) has a cumulative target of 25%, 50%, 75%, and 100% of the annual payment. Withholding is treated as paid evenly through the year.
- Next payment = cumulative target for the next due date − estimated payments already made.
Before you rely on this
Not tax, legal, or financial advice. Safe harbor avoids the underpayment penalty; it doesn’t mean you owe nothing more. If 2026 tax ends up higher, the balance is still due by April 15, 2027. Special rules apply to farmers and fishermen, fiscal-year filers, and people whose 2025 return didn’t cover 12 months. See Form 1040-ES, Publication 505, and Form 2210, or ask a professional.
Official sources & tax year
Frequently asked questions
What is the safe harbor rule for estimated taxes?
You generally avoid the underpayment penalty if withholding plus on-time estimated payments cover at least the smaller of 90% of your 2026 tax or 100% of your 2025 tax. The 100% becomes 110% if your 2025 adjusted gross income was over $150,000 ($75,000 married filing separately).
What is the 110% rule?
Higher earners (2025 AGI over $150,000, or $75,000 married filing separately) must pay 110% of last year’s total tax, instead of 100%, to use the prior-year safe harbor.
When are 2026 estimated tax payments due?
April 15, 2026; June 15, 2026; September 15, 2026; and January 15, 2027. You can skip the January payment if you file your 2026 return by February 1, 2027 and pay the full balance with it.
Do I still owe tax if I hit safe harbor?
Possibly. Safe harbor only protects you from the underpayment penalty. If your actual 2026 tax is higher than what you paid, you still owe the difference by April 15, 2027.
Do I have to make estimated payments at all?
Generally not if you expect to owe less than $1,000 after withholding and credits, or if you had no tax liability for 2025 and were a US citizen or resident for the whole year.