Quarterly Tax Penalty Calculator
Missed a quarterly payment? Enter what you paid (or didn't) and see your estimated IRS underpayment penalty — plus what to do about it now.
Used to estimate your total tax liability this year
Your total tax from last year's return. Paying 100% of this (safe harbor) avoids penalties even if your income grew.
Quarterly Payments Made
Enter $0 or leave blank for quarters you skipped
Q1 2026
Due Apr 15, 2026
Q2 2026
Due Jun 16, 2026
Q3 2026
Due Sep 15, 2026
Q4 2026
Due Jan 15, 2027
Estimated Underpayment Penalty
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Enter your income and quarterly payments to see your penalty estimate.
The IRS charges a penalty when you underpay quarterly estimated taxes. This calculator uses the IRS simplified method (Form 2210) to estimate what you owe per quarter you missed or underpaid.
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Penalty estimated using IRS underpayment rate × underpayment × (days/365) per quarter. Actual IRS penalty uses daily compounding and may differ. Based on simplified Form 2210 method. Not tax advice — consult a CPA to calculate the exact amount and explore penalty waiver options.
Penalty estimated using simplified Form 2210 method. Actual IRS penalty uses daily compounding — this is an approximation. IRS underpayment rates are set quarterly; this calculator uses best available 2026 rates. Not tax advice.