If you filed late, paid late, or both, the IRS adds penalties and interest on top of the tax. The numbers grow every month, and the IRS bill doesn’t explain much.
I built this calculator so you can see roughly what you owe and where it comes from. Enter your tax year, the balance, and your dates, and you’ll get a breakdown of each penalty, the interest, and a few ideas that may lower it.
I’m Solomon Grosinger, an IRS-licensed Enrolled Agent in Brooklyn since 2017. I help individuals, businesses and trusts with the IRS, New York, New Jersey, Connecticut and Pennsylvania. If your number looks high, book a free consultation and we can look at your options.
IRS Penalty and Interest Calculator
Estimate the late filing penalty, late payment penalty and interest on a federal income tax balance (Form 1040). Uses the IRS interest rates through the end of 2026.
This is a simplified estimate. It assumes the full balance stays unpaid until the payoff date, so if you pay over time your real numbers will be lower. It leaves out interest on the late payment penalty (the IRS starts that after it sends a bill), the higher 1% rate after a final notice of intent to levy, disaster postponements, and estimated tax penalties. Rates after December 31, 2026 are assumed to stay at 7%. Sources: IRC 6651 and 6621, IRS failure to file and failure to pay penalty pages, and IRS quarterly interest rates (7% for the fourth quarter of 2026, Rev. Rul. 2026-15). Minimum late filing penalty for returns due in 2026: $525.
General info, not advice for your specific case.