Here's the good news: an audit letter rarely means criminal trouble or a six-figure tax bill. In fiscal year 2025, the IRS closed 497,621 return examinations, and 81% were handled entirely by mail, according to the IRS's 2025 Data Book. Most audits check a handful of line items, nothing more.
This guide covers how to confirm your letter is genuine, the different audit types, a step-by-step response plan, common mistakes to avoid, and what happens if you disagree with the outcome.
Key Takeaways
- Verify the CP or LTR number on IRS.gov before sharing any personal or financial information
- Most audits (81%) are correspondence exams resolved entirely through the mail
- Missing a response deadline can forfeit your appeal rights and trigger automatic adjustments
- Form 2848 lets a CPA or enrolled agent speak to the IRS so you don't have to
- Organized, targeted responses resolve far more audits than silence or guesswork ever will
Decoding Your IRS Audit Letter: Key Notice Types and How to Verify Them
Every legitimate IRS letter carries a CP (Computer Paragraph) or LTR (Letter) number, usually printed in the upper right corner of the first page. This number tells you exactly what the IRS wants and why.
How to Verify an IRS Letter Is Legitimate
Before you respond to anything, confirm the letter is real:
- Locate the CP or LTR number in the top right corner
- Search that exact number on IRS.gov's notice lookup tool
- Call 800-829-1040 if the notice doesn't match anything official
- Remember the IRS never demands payment by gift card or cryptocurrency, and it never opens contact by text or email
JFT Group flagged exactly this kind of fraud in a recent post about a fake "IRS Digital Asset Compliance Portal" letter circulating by mail. The format looked official. It wasn't.
Common IRS Audit Letters and Notices
Different letters serve different purposes, and confusing them can waste your limited response window.
| Notice | What It Means | Typical Deadline |
|---|---|---|
| CP2000 | Proposes changes because third-party income data (W-2s, 1099s) doesn't match your return. It's a proposal, not a bill. | Generally 30 days from the notice date, per IRS Topic 652 |
| Letter 566 | Initial contact for a correspondence audit, identifying questioned items | Date stated on the letter |
| Letter 2205 series | Initiates a field examination, often via a revenue agent | Date stated on the letter |
| Form 4564 (IDR) | Lists specific documents, accounts, and tax years under review | Case-specific, noted on the form |
Note the postmark or notice date the day you receive anything. These dates anchor statutory deadlines that don't bend for lost mail or vacation schedules.
The Three Types of IRS Audits Explained
The IRS classifies audits into three tiers based on complexity. Most taxpayers never see the inside of an IRS building.
Correspondence Audits (Mail Examinations)
These happen entirely through the mail or a secure IRS document portal. They usually target specific items: a charitable deduction, a 1099 mismatch, an education credit.
Send photocopies, not originals, along with a short written explanation of how you arrived at the number in question. Organized receipts paired with clear notes close most of these cases without further back-and-forth.
Office Audits (Desk Audits)
Here, you or your representative meet an IRS examiner in person at a regional IRS office. The examiner reviews selected books and records tied to a defined set of questions, not your entire financial history.
Field Audits (On-Site Examinations)
Field audits are the most thorough. A revenue agent visits your home, your business, or your representative's office to review general ledgers, bank deposits, and internal controls.
Cash-heavy businesses and multi-state contractors draw heightened scrutiny here. Restaurants, paving crews, and trades that move job to job often struggle to document cash flow the way an agent expects, which is exactly why detailed books matter long before a letter arrives.
Step-by-Step Guide: What to Do Immediately After Receiving an Audit Letter
Panic leads to mistakes. A methodical approach doesn't.
Read the notice thoroughly and identify the exam scope. Pin down the exact tax years, income items, and deductions in question. An audit of your 2023 Schedule C doesn't put your entire filing history on trial.
Assemble, match, and reconstruct your financial records. Gather bank statements, canceled checks, mileage logs, and receipts tied to the specific items requested. If records are missing, reconstruct them from merchant statements, third-party confirmations, or sworn affidavits. Never hand an auditor a disorganized box of paperwork; it invites more questions than answers.
Secure qualified professional representation. Under IRC §7521, you have the right to pause an interview and consult a CPA, enrolled agent, or tax attorney. A properly authorized representative can speak to the IRS without you present. JFT Group handles this for clients regularly: filing Form 2848, managing IRS correspondence, and rebuilding missing books for contractors and business owners.
Deliver a targeted, substantiated response before the deadline. Send only what's requested, no more, using certified mail with return receipt requested. Volunteering extra documents can widen the scope of an otherwise narrow audit.
Critical Mistakes to Avoid When Responding to the IRS
Small missteps turn manageable audits into expensive ones.
- Ignoring the notice or missing deadlines. Silence can lead to automatic disallowance of credits, a Notice of Deficiency, and the loss of your right to appeal administratively.
- Volunteering unnecessary information or guessing at numbers. Speculating during an interview, or handing over unsorted records, can pull additional tax years into scope.
- Trying to handle a complex business audit alone. One JFT Group client faced a $210,000 tax levy covering 2016 through 2018 after years of filings with no real books. Without records, the IRS and the state simply levy what they see fit.
If your situation involves undocumented cash expenses, multi-state operations, or years of thin recordkeeping, that's the point to call in professional representation rather than negotiate solo.
Possible Audit Outcomes and Your Rights to Appeal
Every audit ends one of three ways.
Three Possible Audit Outcomes
- No Change – your return is accepted exactly as filed
- Agreed – you accept the proposed adjustments and sign Form 870
- Unagreed – you dispute the findings and intend to push back
Navigating the IRS Appeals Process
An unagreed case typically triggers a 30-day letter, giving you 30 days to request a conference with the independent IRS Office of Appeals. Many disputes settle at Appeals without ever going to court.
If Appeals doesn't resolve things, the IRS issues a 90-day Statutory Notice of Deficiency. From there, you can petition the U.S. Tax Court, generally within 90 days of that notice's mailing date, according to the U.S. Tax Court. Miss that window, and your remaining options narrow considerably.
Frequently Asked Questions
What will trigger an IRS audit?
Common triggers include DIF computer scoring anomalies, mismatches between your return and W-2/1099 data, unusually high business expense ratios, and random compliance sampling.
How long after filing can you get audited?
The standard window is three years from your filing date, extending to six years if you omitted more than 25% of your income, and indefinitely for unfiled returns or suspected fraud.
Are there fake IRS letters being sent out?
Yes. Genuine IRS letters never demand payment by gift card or cryptocurrency, and the IRS never initiates contact by text or email. When in doubt, verify the notice number on IRS.gov directly.
What does the IRS look at when they audit you?
Form 4564 Information Document Requests typically ask for bank deposits, business revenue records, itemized deductions, payroll records, and supporting receipts tied to specific line items.
How long can the IRS hold your refund for review?
It varies. The IRS can hold a refund while verifying identity, resolving income mismatches, or reviewing audit issues, a process that can take anywhere from several weeks to a few months depending on how quickly you respond.
How serious is an audit?
Most audits are routine civil checks resulting in minor adjustments or no change at all. Ignoring one, however, can lead to real consequences: penalties, liens, and accumulating interest.
