How Long Does an IRS Tax Audit Last?

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When clients first learn they are under IRS examination, one of their first questions—right after “How bad is this?” is “How long will it take?” Unfortunately, there is no one-size-fits-all answer. An audit can last as little as a few months or stretch into several years. Understanding the variables that affect audit duration helps taxpayers set realistic expectations and adopt strategies that minimize delays. If you have found yourself under an IRS or California tax audit, it is in your best interest to contact the Tax Law Offices of David W. Klasing today.

Whether you have been notified of an upcoming audit, are awaiting the IRS’ determination in your case, or suspect that a criminal tax investigation has begun, the time is now to reach out to a dual licensed Tax Attorney and CPA to help you with your defense. Learn more about the services that the Tax Law Offices of David W. Klasing provides by calling us at (800) 681-1295 or scheduling online to arrange a reduced rate initial consultation.

Types of IRS Audits and Typical Timelines

Correspondence Audits

Conducted entirely by mail, these focus on narrow issues—say, a charitable-contribution deduction or Earned Income Tax Credit documentation. If you respond promptly and the IRS is satisfied, the audit can wrap up in under six months. Delays occur when taxpayers ignore letters, submit incomplete documentation, or the IRS backlog lengthens.

Office Audits

These require a trip to an IRS office and generally involve broader issues—self-employment income, rental real-estate expenses, or retirement-plan rollovers. Office audits often span nine to twelve months from the initial notice to closing. Preparatory meetings with your adviser, timely submission of records, and well-organized explanations can shorten this timeline.

Field Audits

The most comprehensive examinations, field audits send revenue agents to your place of business. They scrutinize bank statements, internal controls, and accounting systems. Multi-entity businesses can expect a year or more. Complex partnerships, international issues, or forensic tracing may push a field audit past the two-year mark.

Key Factors That Influence Duration

Scope of Issues

If your return includes cryptocurrency transactions, passive-activity losses, and foreign trusts, the agent may need specialists, each adding weeks or months.

Responsiveness

The IRS typically gives 30 days to provide requested records. Every missed deadline prompts follow-up letters, adding at least another month.

Target Cooperation

But the most substantial factor in any case that could affect an audit’s timeline is target cooperation. This does not just refer to a taxpayer’s willingness to provide financial information. The most common causes of audit timeline extensions that we see all the time are simple taxpayer mistakes when attempting to comply with an audit including books and records that simply do not make sense or are incomplete or unreliable.

Quality of Records

Organized digital files expedite review. Boxes of unsorted receipts prolong it. Missing records trigger summonses or third-party inquiries, dramatically expanding the timeline.

Statute of Limitations

Generally, the IRS has three years to assess additional tax, extended to six years if gross income is understated by 25 percent or more, and indefinitely for fraud. Agents pace their exams to finish before the deadline, but if the clock is ticking, they may ask you to sign a consent to extend the statute of limitations. Refusing doesn’t automatically end the audit; instead, the agent may issue a Notice of Deficiency sooner, pushing the matter to Appeals or Tax Court.

COVID-19 and Post-Pandemic Backlogs

Though IRS field operations are largely normalized, residual backlogs still affect correspondence times. E-filing and digital document uploads mitigate, but cannot eliminate, delays.

Stages of an Audit

Initial Contact – A 566 letter announces the audit and requests documents.
Information Gathering – Agent reviews records, asks follow-up questions, and possibly contacts third parties.
Preliminary Findings – You receive a Form 4549 (Revenue Agent Report).
Discussion/Negotiation – Provide rebuttal evidence, request conference with a supervisor if necessary.
30-Day Letter – If unresolved, this letter outlines proposed adjustments and offers an Appeals route.
Appeals – Adds three to twelve months, depending on complexity and backlog.
Tax Court – Should you petition, litigation can extend another year or more, though many cases settle beforehand.

How Long Does the IRS Have to Complete a Tax Audit?

It’s important to draw a distinction between the timeline for an audit and the statute of limitations for an audit. The latter can impact the former, but they are separate issues. The timeline for an audit is how long the auditing process itself will take. By comparison, the statute of limitations determines how far back into the taxpayer’s records the auditor may probe. Depending on the situation, the statute of limitations may allow the auditor to review tax returns and related records from up to three years ago, from up to six years ago, or from any point in the taxpayer’s history – even a tax return that is 15 or 20 years old. For more information about this subject, our IRS tax audit lawyers would encourage readers to explore the following articles:

While the statute of limitations on a tax audit generally ranges from three to six years (in cases where a limit exists), that does not mean a tax audit will require three to six years for the auditor to complete. As we will discuss momentarily, most audits conclude far sooner. However, as noted above, the statute of limitations can impact the timeline of an audit by creating boundaries for the examination of aging records.

Assuming the three-year statute of limitations applies – which, to reiterate, would not be the case if the audit involved egregious issues, such as a substantial understatement of the taxpayer’s income or evidence of tax fraud– the IRS has 36 months from the date of filing to examine the relevant tax return. However, eight of those months must be allotted for the processing of any appeals, meaning protests that are filed by the taxpayer. (Not everyone who is audited chooses to protest an IRS audit decision, or litigate if the matter is not solved in appeals, but taxpayers generally have the right to these options should questionable audit return findings arise because of differences in opinion on the facts or law underlying the audit.) With these eight months accounted for, the IRS has 28 remaining months – two years and four months – in which to perform the audit. Again, these limits would be extended if the IRS suspected serious violations or criminal activity, or if the taxpayer voluntarily allowed the IRS to extend the statute of limitations which should not be agreed to without the advice of qualified counsel.

The aforementioned does not mean the audit itself will take 28 months to complete – but it does create a framework the auditor must stay within. Most audits conclude within several months to about one year, but the precise duration of an audit depends heavily on three interrelated factors: (1) what type of audit is being conducted, and (2) the number and severity of the issues detected and the changes proposed (3) the efficiency and competence of the auditor and their manager. Needless to say, an audit which reveals a complex web of tax evasion will require more time for completion (and will invariably be accompanied by taxpayer fear and anxiety of subsequent or simultaneous IRS criminal investigation) than an audit which reveals a basic accounting error, or which turns on missing receipts & documents.

When Audits Outlast Patience

Sometimes, despite best efforts, an audit lingers. You may file a Taxpayer Advocate Service request if delays cause significant hardship. Another tool is IRS escalation: ask to speak to the agent’s manager. Persistent delays may justify lodging a formal complaint or seeking congressional assistance—but these steps should be strategic, guided by counsel, and reserved for genuine gridlock.

Tactics for Keeping an Audit on Track

Centralize Records – A single electronic folder with labeled PDFs streamlines communication.
Set a Response Calendar – Don’t rely on memory; missing a due date prolongs the exam and irritates the agent.
Avoid Scope Creep – Uniform, accurate responses discourage agents from expanding inquiries.
Consider a Limited Statute Extension – Agreeing to a short extension (e.g., six months) can buy time for Appeals without allowing the audit to drag indefinitely.

Should You Be Worried If Your IRS Audit Agent Goes Quiet?

If an audit is dragging out longer than expected and you or your representative reach out to the IRS agent in charge of conducting the audit. If the agent in your case is difficult or impossible to get a hold of, you may chalk it up to a heavy workload or government incompetence. However, you should know that noncommunication from an IRS audit agent could mean something much more worrisome.

When an auditor uncovers information that suggests willful intent to evade taxation or some other criminal tax offense, the agent in charge of the audit is responsible for turning the case over to another agent in the IRS criminal investigations department. During this transition, the original agent is instructed to avoid contact with the subject of the audit. You likely will not find out that your audit has transitioned into a criminal tax investigation until the government has the information it needs to attempt to prosecute you. The investigation often proceeds along in secret to take their target by surprise and prevent any possible destruction of evidence.

If you can’t contact your auditor, you may be facing something tremendously bigger than you originally may have been contemplating. At this point, you should reach out to the dual licensed Tax Attorneys and CPAs at the Tax Law Offices of David W. Klasing as soon as possible.

When Will an IRS Audit Result in a Criminal Tax Investigation?

If during an audit, an auditor becomes aware of badges of fraud, which are factors that the IRS has come to associate with fraudulent tax filings, the auditor may request to be secretly assisted by an IRS fraud technical advisor (FTA). The FTA will weigh any observed badges of fraud and decide if the audit should be stopped and the matter referred over to the criminal investigation unit for a closer look or not. If, for example, your reported income sees a sudden and unexplained drop in a single year, and an undisclosed domestic or foreign bank account is discovered that contains unreported deposits, this would trigger further scrutiny. If an agent comes across information that you have undisclosed foreign bank accounts required to be reported on an FBAR, coupled with income tax evasion related to the offshore account, the matter is likely to be referred for potential criminal tax investigation and prosecution.

Investigations are also more common in cash-intensive industries like restaurant, bar, and hospitality businesses. Of course, failing to file your tax returns at all is also highly likely to attract negative attention toward you. In terms of criminal tax investigations specifically, being involved in any of the IRS’s dirty dozen tax fraud schemes or using something like a micro-captive insurance company to avoid paying what you owe are highly likely to get an FTA’s attention and move things from a civil to a criminal level. There are also certain situations where information is shared with the IRS by other agencies or another investigation within the agency that can prompt an agent to open an eggshell audit or criminal tax investigation into your behavior.

For example, if the IRS raids a check cashing business and finds large amounts of checks written to you personally or to your business, they will likely audit you to look for unreported income. Another example would be undisclosed cryptocurrency information that the IRS obtains because of an unrelated case against Coinbase or other cryptocurrency trading hubs. If there is at least $10,000 of unreported income that shows up in an audit, the auditing IRS agent will almost certainly consult with an FTA, who will analyze the badges of fraud in your audit for potential development by the criminal investigation unit.

What Should I Do If My IRS Audit Results in a Criminal Tax Investigation?

You should never go through any type of eggshell audit or criminal tax investigation without the assistance and expertise of an experienced criminal tax defense attorney like those at The Law Offices of David W. Klasing. However, once there has been some sort of indication that the matter has been or may be referred to the CI unit, it is even more important that you have an attorney who knows how to protect your rights and interests during the investigation. If the CI unit chooses to develop your matter for prosecution, they have a 90% conviction rate. If you reach out to us before criminal charges are filed, we may be able to reach out to the eggshell auditor, CI agent and any U.S. Attorney assigned to your case and negotiate some sort of deal for you to resolve the outstanding matters in exchange for, at best, no criminal charges being filed, to at worst, reduced or minimized criminal charges being filed. Of course, even if criminal tax charges have already been filed, we can work to minimize the severity of the punishment related to the criminal tax charges in addition to minimizing fines, interest, restitution, and other potential conditions like supervised release.

Role of Professional Representation

Experienced counsel does more than defend deductions. At the Tax Law Offices of David W. Klasing, we can:

Identify information requests that exceed statutory authority, trimming unnecessary document hunts.
Negotiate reasonable document-production timelines.
Present concise, well-indexed evidence, saving the agent from sifting through irrelevant data, often rewarded with a faster close.
Prepare closing agreements or fast-track settlements, avoiding the need for protracted Appeals.

Predicting audit length is part art, part science. Correspondence audits may close quickly, while field audits can take years. Document quality, issue complexity, and your engagement style all influence the timeline. By preparing thoroughly and responding promptly, you control the one variable entirely within your grasp: cooperation.

If you have received an IRS audit notice or need help cutting through delays, reach out to The Tax Law Offices of David W. Klasing. Our team combines procedural know-how with tax-technical depth to move your audit toward a timely and favorable resolution.

The Tax Law Offices of David W. Klasing Can Help You with Your IRS Audit

It is not in your best interests to undergo an audit without the benefit of robust and aggressive audit representation. Without an experienced tax attorney or better yet, a dually licensed Attorney-CPA at your side, you are at heightened risk of receiving costly assessments of additional tax, penalties and interest, accidentally criminally incriminating yourself, missing steps and deadlines that are necessary for a successful appeal, and making other preventable errors that at a minimum could bring you financial or legal harm, and in worst case scenarios lead to criminal tax prosecution, conviction and loss of professional licensure.

Get the facts about IRS audit behavior and what to expect in your case by calling the dual licensed tax Attorneys and CPAs at the Tax Law Offices of David W. Klasing by calling (800) 681-1295 or scheduling a reduced rate initial consultation online here.