Internal Revenue Code section 6213 supplies the general deadline for asking the United States Tax Court to redetermine a deficiency before the IRS assesses it. The statutory notice of deficiency is therefore more than an examination letter: it can open a limited path to prepayment judicial review.
Read the notice, not a general calendar
The general domestic petition period is 90 days from mailing. Different rules can apply to certain notices addressed outside the United States. Weekend and legal-holiday rules may affect the last day. The notice’s date, address, tax periods, addressee, and stated last day to petition should be preserved and independently checked.
Administrative disagreement is not a petition
Continuing to correspond with an examiner, calling the IRS, sending documents, or requesting reconsideration generally is not the same as filing a Tax Court petition. The statutory filing requirement must be satisfied through an accepted filing method.
The underlying case still must be developed
Protecting the petition period is the first procedural question. The merits require the return, examination report, workpapers, substantiation, legal positions, and procedural history. Filing merely to gain time is not a substitute for analyzing jurisdiction and the disputed adjustments.