The U.S. Tax Court is the one court where you can challenge an IRS deficiency without paying the tax first. Your ticket in is a petition filed against a Statutory Notice of Deficiency (CP3219N / Letter 3219, the “90-day letter”) — and the 90 days in that name is the hardest deadline in this entire cluster. This page covers Tax Court for deficiency cases only: the ticket the IRS sends when it wants to assess more tax after an audit.
General information, not tax or legal advice. The 90-day deadline is statutory and jurisdictional. If you are anywhere near it, file the petition first and polish later — a timely imperfect petition preserves rights that a perfect late one cannot.
Under IRC §6213(a), a petition must be filed within 90 days after the notice of deficiency is mailed — 150 days if the notice is addressed to a person outside the United States. The last day is printed on the notice itself. Key properties of this clock:
Filing on time does real work: while a timely petition is pending, the IRS is barred from assessing or collecting the disputed deficiency until the Court’s decision becomes final.
The Court’s own Guidance for Petitioners keeps this deliberately simple:
You may file electronically through DAWSON (ustaxcourt.gov/dawson), the Court’s own e-filing system — despite stale third-party FAQs still claiming Tax Court e-filing does not exist, it does — or by mail or hand delivery to the Court in Washington, DC.
If the amount in dispute — the deficiency plus penalties — is $50,000 or less for any one tax year, you may elect small tax case (“S”) procedures under §7463. Hearings are informal, faster, and designed for self-represented taxpayers. The trade-offs are structural, not incidental:
For a straightforward records dispute under the threshold, S procedures are usually the right door. For an issue you might need to appeal, or one with value beyond this case, get advice before electing.
Most docketed cases never reach a judge. The IRS answers the petition, and cases are routinely referred back to the IRS Independent Office of Appeals for settlement discussions — the Appeals process with a docket number attached. If settlement fails, the case is set on a trial calendar for your designated city, and a judge decides the disputed issues on the evidence. If the deadline was missed entirely, the Tax Court door is closed: the IRS assesses, and the remaining judicial route is to pay and sue for a refund in federal district court or the Court of Federal Claims.
Two neighbouring tickets this page does not cover: a petition to review a Notice of Determination from a Collection Due Process hearing (a levy/lien notice, not a deficiency) carries a 30-day deadline and is a different process — see Collection Due Process hearings; and Tax Court review of a denied interest-abatement claim (§6404(h)) has its own petition route — see IRS interest abatement.
How do I get to the Tax Court? With a Statutory Notice of Deficiency — that notice is your ticket in. File a petition on Form 2 within 90 days after the notice is mailed, attach a copy of the notice and the Statement of Taxpayer Identification Number, and pay the $60 filing fee (or apply for a waiver). The Tax Court is the only forum where you can challenge the deficiency without paying it first, and while a timely petition is pending the IRS is barred from assessing or collecting the disputed amount.
How long do I have to file a Tax Court petition? 90 days after the notice of deficiency is mailed — 150 days if the notice is addressed to you outside the United States (§6213(a)). If the last day is a Saturday, Sunday or DC legal holiday, the next business day counts. The Court cannot extend this deadline; a petition mailed on the last day is timely under the timely-mailed/timely-filed rule (§7502) — keep the certified-mail receipt.
How much does it cost to file a Tax Court petition? The filing fee is $60, payable to the Clerk of the Court (verified on ustaxcourt.gov’s Court Fees page, 2026-10-23 — fees can change, so confirm before you file). A fee-waiver application exists if you cannot afford it. You may file electronically through DAWSON or by mail or hand delivery to the Court in Washington, DC.
What happens if I miss the 90-day deadline to petition Tax Court? The Tax Court door closes — the Court has no power to extend the deadline. The IRS can then assess the deficiency, and the remaining judicial route is to pay the tax in full, file a claim for refund, and sue for the refund in federal district court or the Court of Federal Claims.
Sources: IRC §§6213, 7463, 7502; U.S. Tax Court, “Guidance for Petitioners: Starting a Case” and Court Fees page (ustaxcourt.gov, fee verified 2026-10-23); Tax Court Form 2 petition kit. Currency verified 2026-10-23.