Statutory Notice of Deficiency

IRS Definition

A notice of deficiency, also called a statutory notice of deficiency or 90-day letter, is a legal notice in which the IRS Commissioner determines the taxpayer’s tax deficiency. Tax laws require that the IRS issue a notice of deficiency before assessing additional income tax, estate tax, gift tax and certain excise taxes unless the taxpayer agrees to the additional assessment. The notice of deficiency is a legal determination that is presumptively correct and consists of the following:

  1. A letter explaining the purpose of the notice, the amount of the deficiency, and the taxpayer’s options
  2. A waiver to allow the taxpayer to agree to the additional tax liability
  3. A statement showing how the deficiency was computed
  4. An explanation of the adjustments

More from H&R Block

If you get a statutory notice of deficiency, you have 90 days to file a petition with the U.S. Tax Court to appeal taxes the IRS thinks you owe. You would receive this letter if you didn’t respond to a previous letter allowing you 30 days to appeal within the IRS, or if your appeal was unsuccessful.

If you don’t file a petition with the Tax Court by the deadline shown on the statutory notice of deficiency, the IRS will send you a bill for the tax, penalties, and interest shown on the notice.

Learn everything you need to know about a statutory notice of deficiency.

Or, learn what to do if you receive a deficiency notice and can’t pay.

Get help from an expert

Your local H&R Block tax pro can look into your issue and deal with the IRS for you.

Schedule a Free Consultation

Or call 855-536-6504

Related Information

What You Need to Know About an IRS Statutory Notice of Deficiency

The Statutory Notice of Deficiency is part of a series of notices sent by the IRS to propose additional tax, penalties and interest. Learn more from the tax experts at H&R Block.

How to Handle an IRS Audit

Learn what the IRS is looking for during an audit, the steps you should take to prepare for an IRS audit, and when it's best to get expert help.

Are IRS Mail Audits Really Something to Worry About?

Get the facts about IRS mail audits from the tax experts at H&R Block. Learn how to respond and how long you can expect the audit to last.

Don’t Pay an IRS Penalty Without Looking Into Penalty Relief

The IRS grants four types of penalty relief, but many taxpayers don't ever ask. Learn how to request penalty abatement from the IRS.

How to Handle IRS CP2000 Notices (Underreporter Inquiry)

Learn how the IRS matches your information to generate CP2000 notices, and how to handle one of these underreporter inquiries if the IRS contacts you.

The IRS Offers Alternatives When You Can’t Pay Your Tax Bill

Get the facts from H&R Block about IRS payment options when you can't pay your tax bill, including short-term extensions, monthly payment plans, and more.