How to use the IRS protest deadline calculator
Korea runs a formal pre-assessment review that a taxpayer files before the bill is issued. The federal system reaches the same place by a different route: after an examination the IRS sends a 30-day letter proposing changes, and the taxpayer may protest to the independent Office of Appeals before any tax is assessed. Enter the date on the letter and the calculator returns that protest deadline.
How the days are counted — the day printed on the letter is not counted, matching the day-zero convention in Fed. R. Civ. P. 6(a)(1)(A), and the same rule is used for the no-assessment window, so the two figures stay consistent. A deadline landing on a Saturday, Sunday or legal holiday moves to the next business day under 26 U.S.C. 7503; the calculator shows only the weekend roll-over, so check holidays separately.
Legal basis — the protest window is set by the letter itself under IRS administrative practice described in IRS Publication 5, which is why the days field is editable rather than fixed. The statutory protection comes later: once a notice of deficiency is mailed under 26 U.S.C. 6212, the IRS may not assess the tax for 90 days, and if a Tax Court petition is filed it may not assess until the decision becomes final (26 U.S.C. 6213(a)). Figures are current as of September 2026.
This calculator is for reference only and is not legal advice. Consult a licensed attorney or CPA about your specific situation.
Frequently asked questions
No. The period is set by IRS administrative practice and the letter states the actual date, which is why this calculator lets you change the number of days rather than fixing it at 30.
The IRS normally issues a notice of deficiency, which starts the statutory 90-day period to petition the Tax Court under 26 U.S.C. 6213(a). Whether that is the better path depends on the facts, so talk to a tax professional.