Free Professional Tool

IRS Interest & Penalty Calculator

Estimate underpayment interest, failure-to-file penalties, and failure-to-pay penalties with quarter-by-quarter precision.

Rate table current through 2026 Q2 (Apr-Jun)

Enter Your Details

All fields marked with * are required

Tax Information

Tax Amount Due *

Amount Already Paid

Leave blank or 0 if no payments made

Key Dates

Original Return Due Date *

e.g., April 15 of the tax year

Return was filed on time

Check if you filed by the due date (including extensions)

Actual Filing Date *

Payment Date *

Date the tax was (or will be) paid

Options

Include failure-to-file penalty

5% per month, up to 25%

Include failure-to-pay penalty

0.5% per month, up to 25%

Show detailed breakdown

Ready to Calculate

Enter your tax details, filing dates, and penalty preferences, then click "Calculate Estimate" to see a detailed breakdown of IRS interest and penalties.

Daily interest accrual Quarterly rate support IRC compliant formulas

Frequently Asked Questions

Free 2026 International Tax Filing Checklist

Get our comprehensive PDF checklist covering FBAR, Form 5471, 8865, PFIC, GILTI, and more. Never miss a filing requirement again.

We never spam. Unsubscribe anytime.

Professional Solutions

Need Help with IRS Notices or International Tax?

Responding to IRS penalties and notices requires precision. Let our CPAs with 20+ years of experience review your international tax forms or prepare the supporting workpapers.

Get Your Forms Reviewed Need Workpapers Prepared?