The IRS examination process is the agency’s formal review of a filed tax return, and it moves through predictable stages: selection, a notice identifying what’s being questioned, your documentation response, the agent’s review, a proposed outcome, and either agreement, appeal, or Tax Court. Each stage carries deadlines and rights that determine how much you ultimately pay. Knowing what the IRS can and cannot do at each step is the difference between a narrow adjustment and a much larger bill.
Why Your Return Was Selected
Most audits start with a computer score. The IRS runs every return through its Discriminant Function System (DIF), which rates how likely an audit would produce a change to the reported tax. High-scoring returns go to a human classifier who decides whether to open an examination. A related system, the Unreported Income DIF (UIDIF), specifically scores the likelihood of unreported income.1Internal Revenue Service. Understanding the IRS Examination Process
The other main trigger is information matching. The IRS compares the income figures on your return against what employers, banks, brokers, and clients reported on W-2s and 1099s. A mismatch often generates a notice or a full examination. Audits can also cascade from related returns: if a partnership is audited, its partners’ individual returns may be pulled in too.
Types of Examinations
The format of your audit tells you where it happens, how deep it goes, and how much of your time it will consume.
Correspondence Audits
The correspondence audit is the most common and least intrusive. Everything happens by mail or through the IRS Document Upload Tool. A letter identifies one or two specific items — a questioned deduction, a credit like the Earned Income Tax Credit, or a piece of unreported income — and asks for supporting documents by a stated deadline.2Taxpayer Advocate Service. Letter Notifying Taxpayer of Audit with Request for Additional Information The scope stays limited to the items listed. Send copies, not originals.
Office Audits
An office audit is an in-person meeting at a local IRS office with a Tax Compliance Officer. The IRS uses this format for issues that need more than a document swap, like Schedule A itemized deductions or Schedule C business expenses. The notice tells you the date, time, and the specific records to bring. The scope is broader than a correspondence audit but stays generally tied to the schedules or line items identified up front.
Field Audits
A field audit is the most thorough. A Revenue Agent comes to your business or your representative’s office to work through the books in detail. The IRS reserves this format for larger businesses, complex partnership returns, and individuals with significant business income. Field audits often cover multiple tax years and touch nearly every part of your financial records. The agent issues formal Information Document Requests (IDRs) to obtain specific books and records, and the examination can run many months. Getting professional representation matters here because the scope is wide and casual conversation can open new issues.
Your Rights Once the Notice Arrives
The Taxpayer Bill of Rights applies from the moment you receive the audit notice through final resolution. Several rights are directly useful during an examination:3Internal Revenue Service. Taxpayer Bill of Rights
- The right to pay no more than the correct amount of tax legally due, including penalties and interest.
- The right to retain an attorney, CPA, or Enrolled Agent to handle all IRS communications, or to seek help from a Low Income Taxpayer Clinic if you cannot afford representation.
- The right to a fair and impartial administrative appeal of most IRS decisions, and to take your case to court.
- The right to privacy — any IRS inquiry must comply with the law and be no more intrusive than necessary.
- The right to challenge the IRS’s position, provide additional documentation, and expect the agency to consider your arguments promptly.
- The right to finality: to know the maximum time the IRS has to audit a year or collect a debt, and to know when an audit is finished.
You can also record any in-person interview. The statute simply requires an “advance request,”4Office of the Law Revision Counsel. 26 USC 7521 – Procedures Involving Taxpayer Interviews but internal IRS procedures require your request to reach the agent at least 10 calendar days before the interview. Miss that window and the agent can allow the recording anyway or reschedule.5Internal Revenue Service. Internal Revenue Manual 4.10.3 – Examination Techniques
Building Your Documentation
Preparation drives outcomes more than anything else. Start organizing as soon as the notice arrives. Waiting until the deadline is near leaves no time to fill gaps.
Pull together bank statements, canceled checks, invoices, receipts, and any contemporaneous logs that tie to the items being questioned. The goal is to substantiate every deduction and income figure on the return. Federal law requires taxpayers to keep records sufficient to support items reported,6Office of the Law Revision Counsel. 26 USC 6001 – Notice or Regulations Requiring Records, Statements, and Special Returns and the burden of proof sits with you. Missing records usually means the deduction gets disallowed.
Some categories carry heightened standards. Business vehicle use generally requires a contemporaneous log with mileage, date, destination, and business purpose for each trip. Charitable contributions above $250 need a written acknowledgment from the recipient organization. Reviewing what you have before the IRS sees it lets you spot weaknesses and, where possible, obtain replacement documentation in time.
Information Document Requests
In office and field audits, the agent asks for specific documents through an IDR. Read each one carefully and provide exactly what’s requested, nothing extra. Volunteered records can point the agent toward issues that weren’t on the table, expanding the scope in ways that rarely help.
Many audit responses can now go through the IRS Document Upload Tool. You’ll need either an access code from your notice or the notice or letter number, plus identifying information. The tool accepts JPGs, PNGs, and PDFs and confirms receipt.7Internal Revenue Service. IRS Document Upload Tool For correspondence audits, uploading beats mailing.
Check the Statute of Limitations Before Anything Else
Before you send documents or sign anything, figure out how much time the IRS has left to assess additional tax. The default window is three years from the later of the return’s due date or the date you actually filed.8Internal Revenue Service. Time IRS Can Assess Tax That expands to six years if you omitted gross income exceeding 25% of what you reported.9Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection There is no time limit at all on a fraudulent return or an unfiled one.
If the deadline is approaching and the agent isn’t finished, the IRS will ask you to sign Form 872, Consent to Extend the Time to Assess Tax, which pushes the deadline to a specific future date.10Internal Revenue Service. Publication 1035 – Extending the Tax Assessment Period Don’t sign automatically. Refusing forces the IRS to either close the case or issue a Notice of Deficiency immediately, which gives you the right to petition Tax Court. On the other hand, if the agent is close to a favorable outcome, extra time can work for you.
When you do extend, you can negotiate a restricted consent limited to specific issues. The IRS also uses Form 872-A, an open-ended consent that doesn’t expire on a fixed date and instead terminates 90 days after either side triggers it.11Internal Revenue Service. Internal Revenue Manual 25.6.22 – Extension of Assessment Statute of Limitations by Consent Fixed-date Form 872 consents are generally safer because they have a definite endpoint.
Getting Representation
You can be represented by an attorney, CPA, or Enrolled Agent authorized to practice before the IRS. Filing Form 2848, Power of Attorney and Declaration of Representative, directs examination correspondence and communications to your representative.12Internal Revenue Service. About Form 2848, Power of Attorney and Declaration of Representative You can also authorize a representative through your IRS online account.13Internal Revenue Service. Power of Attorney and Other Authorizations
Most experienced representatives advise clients not to attend the audit meeting. Your presence invites direct questions, and an offhand answer can open lines of inquiry the agent hadn’t planned. The representative handles procedural and factual questions from the prepared documentation. If the agent insists on speaking with you, the representative can pause to consult.
Hourly rates for CPAs and Enrolled Agents handling audit representation generally run from $150 to over $500 per hour, with complex field audits at the upper end. If you can’t afford representation, the Taxpayer Advocate Service accepts cases involving economic or systemic hardship,14Internal Revenue Service. Internal Revenue Manual 13.1.7 – Taxpayer Advocate Service Case Criteria and Low Income Taxpayer Clinics provide free or reduced-cost representation for those who qualify.
Keeping the Examination on Track
Once the agent has your records, the middle phase consists of their review, follow-up IDRs, and back-and-forth with your representative. Your representative’s job is to keep responses tied to the original scope. If the agent starts asking for records unrelated to the items in the initial notice, the audit is drifting into a fishing expedition. Absent a clear pattern of non-compliance, the examination should stay within its original boundaries.
For field audits, the IRS generally works at your principal place of business, but you can ask that the examination be held at your representative’s office instead. That minimizes disruption and keeps the agent away from employees, filing cabinets, and informal conversations that might spawn new questions.
How the Audit Ends
When the agent finishes, one of three things happens.
No-Change Letter
If the agent concludes your return was correct as filed, the IRS issues a no-change letter and the audit is over. A no-change result also helps guard against repeat audits: the IRS has procedures to screen out examinations targeting the same issues examined in either of the two preceding years when those prior audits produced no change or only a small adjustment.
Agreeing to the Adjustments
If you agree with the findings, you sign Form 870, Waiver of Restrictions on Assessment and Collection of Deficiency in Tax.15Internal Revenue Service. IRS Form 870 – Waiver of Restrictions on Assessment and Collection Signing lets the IRS immediately assess the deficiency. The practical benefit: if the IRS doesn’t send you a bill within 30 days of your filing the waiver, interest is suspended from that 30th day until the IRS actually issues notice and demand for payment.16Office of the Law Revision Counsel. 26 USC 6601 – Interest on Underpayment, Nonpayment, or Extensions of Time for Payment, of Tax With interest compounding daily at current rates, that pause can save real money.
Disagreeing With the Adjustments
If you disagree, the IRS sends a 30-day letter — typically Letter 525 — with the examination report detailing the proposed adjustments. You have 30 days from the date of the letter to accept the adjustments or file a written protest requesting a conference with the IRS Independent Office of Appeals. Miss the 30 days and the IRS moves to a Statutory Notice of Deficiency.17Taxpayer Advocate Service. Letter 525 Audit Report/Letter Giving Taxpayer 30 Days to Respond
A formal protest identifies the disputed adjustments, lays out the facts, and explains the legal arguments for your position. It’s the gateway to Appeals, and a well-drafted one significantly improves your odds.
The Appeals Office
The IRS Independent Office of Appeals sits apart from the examination division. Its purpose is to resolve disputes short of litigation, and Appeals Officers have authority examiners lack: they can weigh the “hazards of litigation,” meaning they can settle based on the realistic chance the IRS would prevail in court. An examiner has no such flexibility. The case is either substantiated or it isn’t.
An Appeals conference is an informal settlement discussion, not a court proceeding. The Appeals Officer reads your protest alongside the agent’s report and looks for weaknesses in the IRS’s position. A protest that pinpoints specific legal and factual problems in the agent’s reasoning gives the Appeals Officer a basis for concessions. Vague objections accomplish little.
If the conference produces agreement, you sign a closing agreement that binds both sides. If it doesn’t, the case moves to a Statutory Notice of Deficiency.
Fast Track Settlement
Before or alongside the formal Appeals route, you can request Fast Track Settlement, a voluntary mediation program that brings an Appeals mediator into the case while the examination is still open. The mediator facilitates discussion but cannot force a resolution.18Internal Revenue Service. Fast Track For individuals and small businesses, the IRS targets resolution within 60 days of accepting the application (Form 14017). Fast Track doesn’t waive your right to a full Appeals conference if mediation fails.
Notice of Deficiency and Tax Court
If Appeals can’t resolve the case, or if you skipped Appeals by not responding to the 30-day letter, the IRS issues a Statutory Notice of Deficiency, commonly called the 90-day letter. It’s the last formal step before litigation.19Internal Revenue Service. Letters and Notices Offering an Appeal Opportunity
You have exactly 90 days from the date of the notice to file a petition with the United States Tax Court. If the notice is addressed to you outside the United States, you get 150 days.20Internal Revenue Service. Internal Revenue Manual 4.8.9 – Statutory Notices of Deficiency Miss the deadline and the deficiency is assessed automatically. Your only remaining option is to pay the tax first and sue for a refund in federal district court or the Court of Federal Claims. The Tax Court petition filing fee is $60.21United States Tax Court. Court Fees
Tax Court’s main advantage is that you don’t have to pay the tax first. For disputes where the total (including penalties) is $50,000 or less for any single year, you can elect the Small Tax Case procedure, which is faster and less formal.22United States Tax Court. Guidance for Petitioners – About the Court The trade-off: Small Tax Case decisions are final and cannot be appealed by either side.23United States Tax Court. Case Procedure Information Under regular procedures, either side can appeal an unfavorable decision to a federal circuit court.
Penalties and Interest on What You Owe
If the IRS assesses additional tax, the deficiency itself is often only part of the bill.
Interest
Interest on an underpayment runs from the original due date of the return until the date you pay in full.16Office of the Law Revision Counsel. 26 USC 6601 – Interest on Underpayment, Nonpayment, or Extensions of Time for Payment, of Tax The rate is set quarterly at the federal short-term rate plus three percentage points for individuals. For the first quarter of 2026 the underpayment rate is 7%; for the second quarter it drops to 6%.24Internal Revenue Service. Quarterly Interest Rates Interest compounds daily, so the longer a deficiency lingers, the larger the total.
Accuracy-Related Penalty
The most common audit penalty is the accuracy-related penalty under Section 6662: 20% of the underpayment attributable to negligence, disregard of rules, or a substantial understatement of income tax.25Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments A “substantial understatement” for individuals means the understatement exceeds the greater of 10% of the correct tax or $5,000. If you claimed the Section 199A qualified business income deduction, the 10% threshold drops to 5%. The penalty doesn’t apply where you can show reasonable cause and good faith.
Civil Fraud Penalty
When the IRS can prove that part of an underpayment is due to fraud, the penalty jumps to 75% of the fraudulent portion.26Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty Here the burden of proof is on the IRS. Once it proves fraud on any portion, though, the entire underpayment is presumed fraudulent unless you rebut it by a preponderance of the evidence. The civil fraud penalty and the accuracy-related penalty cannot be stacked on the same underpayment.
Paying What You Owe
An assessed balance doesn’t have to be paid in one shot. The IRS offers several arrangements.27Internal Revenue Service. 28Internal Revenue Service. Offer in Compromise The IRS evaluates income, expenses, assets, and ability to pay before accepting.
Reopening a Closed Audit
If you missed deadlines during the examination and the IRS assessed additional tax without your input, or if you have new documentation that wasn’t available during the original audit, you can request audit reconsideration. It isn’t a guaranteed second look, but it reopens the case.29Internal Revenue Service. Internal Revenue Manual 4.13.1 – Examination Audit Reconsideration Process
To qualify, you must have filed the return in question, the assessment must remain unpaid (or involve reversed credits you’re disputing), and you must present new information the IRS didn’t consider originally. IRS computational or processing errors also qualify. Submit the request in writing, ideally using Form 12661, Disputed Issue Verification, with the supporting documentation. Audit reconsideration is not available once you’ve paid the assessment in full. At that point the path is a formal claim for refund.