How long does an IRS audit take?

A correspondence audit typically resolves in 3–6 months. An office audit usually takes 3–12 months. A field audit — the most complex type — can take 1–3 years depending on the issues involved. The IRS has 3 years from your filing date to initiate an audit in most cases (6 years if substantial underreporting is suspected).

What are the chances of being audited?

The overall audit rate for individual returns has dropped significantly over the past decade. For returns with income under $200,000, the audit rate is less than 0.5%. Returns showing income over $1 million face roughly a 2–3% audit rate. Returns with Schedule C (self-employment) or large charitable deductions face higher scrutiny regardless of income level.

Do I need a lawyer or CPA for an IRS audit?

For a simple correspondence audit disputing one or two items, you may be able to respond yourself with good documentation. For office and field audits — particularly those involving unreported income, business deductions, or self-employment — professional representation by a CPA, enrolled agent, or tax attorney is strongly advisable. A professional can speak directly with the IRS on your behalf and knows which documents to provide and which to withhold.

Can I go to jail for failing an audit?

Civil audits — the vast majority — result in additional tax, penalties, and interest. Criminal prosecution for tax evasion requires intentional fraud with the specific intent to evade tax. Simply failing to report income accurately is generally treated as a civil matter unless the IRS determines the underreporting was willful. If a civil audit reveals evidence of intentional fraud, it can be referred for criminal investigation — but this is uncommon.

What happens if I ignore an IRS audit notice?

Ignoring an audit notice is one of the worst things you can do. If you don't respond to a correspondence audit, the IRS will issue a Notice of Deficiency (a '90-day letter') with the proposed additional tax. If you don't respond to that, the IRS will assess the additional tax automatically and begin collection. You'll owe the full proposed amount plus penalties and interest, and you'll have missed your chance to dispute any of it.

Can the IRS audit a return from 5 years ago?

In most cases, the IRS has 3 years from your filing date to audit a return. If you omitted more than 25% of your gross income, the window extends to 6 years. If fraud is involved, there is no statute of limitations. If you never filed a return for a given year, the 3-year clock never starts.

IRS Audit Guide: What to Expect and How to Respond

Receiving an IRS audit notice feels alarming — but understanding what type of audit it is, what triggered it, and exactly what to do next removes most of the uncertainty. The overwhelming majority of IRS audits are resolved through documentation, not courtrooms.

This guide covers everything: the three types of audits, what the IRS is actually looking for, your rights throughout the process, and a step-by-step response plan.

Types of IRS Audits

The IRS conducts three types of audits, and the type you’ve been selected for determines almost everything about what happens next.

Correspondence Audit

The most common type by far — roughly 75% of all audits. The IRS mails you a letter (typically a CP2000 underreporter notice or similar) asking you to verify or explain specific items on your return. Common triggers: a Form 1099 or W-2 that doesn’t match what you reported, a claimed deduction the IRS wants documentation for, or a credit that appears inconsistent with your return.

You respond entirely by mail or fax. No in-person meeting. Most correspondence audits are resolved in 3–6 months.

Office Audit

You’re asked to come to an IRS Taxpayer Assistance Center or field office to discuss your return in person with an IRS employee. Office audits are triggered when the IRS has questions that require a more detailed review than a letter exchange — typically business expenses, rental income, or self-employment deductions. You bring your documentation to the meeting.

Field Audit

The most extensive type. An IRS Revenue Agent comes to your home, business, or your representative’s office. Field audits are typically reserved for complex returns: businesses with significant revenue, real estate investors, taxpayers with offshore assets, or cases where the IRS suspects substantial underreporting. Field audits can take one to three years to resolve.

What Triggers an IRS Audit

The IRS uses a scoring system (the Discriminant Information Function, or DIF score) to rank returns by their statistical likelihood of generating additional tax. Returns with unusually high deductions relative to income, round numbers in multiple line items, and certain schedules are scored higher. Common triggers include:

Income mismatches. Every 1099, W-2, and K-1 you receive is also sent to the IRS. If the income you report doesn’t match what third parties reported, a notice is nearly automatic.

Large charitable deductions. Donations exceeding 20% of adjusted gross income are a consistent audit trigger. Non-cash charitable contributions require Form 8283 and, above $5,000, a qualified appraisal.

Business loss deductions (Schedule C). Self-employed taxpayers who report consistent losses — particularly those with wage income — face elevated scrutiny. The IRS watches for hobby losses being claimed as business losses.

Home office deductions. Claimed by millions of taxpayers; verified by very few. The home office deduction requires exclusive and regular use of a defined space. A guest bedroom used occasionally for work doesn’t qualify.

High unreimbursed employee business expenses. Since the Tax Cuts and Jobs Act of 2017 eliminated most miscellaneous itemized deductions, claiming these on older returns or through Schedule A is a red flag.

Cash-intensive businesses. Restaurants, salons, and other businesses where cash transactions are common face higher audit rates due to the difficulty of verifying income.

Round numbers everywhere. Actual business expenses are rarely round numbers. Returns where every expense is $500, $1,000, or $5,000 suggest estimation rather than recordkeeping.

The Audit Process, Step by Step

Step 1: Initial notice. The IRS sends a notice identifying the tax year under review and the specific items being questioned. Read this carefully — it defines the scope of the audit.

Step 2: Document gathering. Collect records supporting the challenged items. For income, this means statements, 1099s, and bank records. For deductions, this means receipts, mileage logs, bank statements, and credit card records. For charitable donations, acknowledgment letters from the organization.

Step 3: Response or meeting. For correspondence audits, you mail or fax your documentation with a cover letter addressing each issue. For office and field audits, you meet with the examiner (ideally with a representative) and present your records.

Step 4: IRS determination. The examiner reviews your response and issues a Revenue Agent Report (RAR) accepting your return as filed, proposing adjustments, or a combination. You’ll receive a 30-day letter explaining any proposed changes.

Step 5: Agreement or appeal. If you agree with the proposed changes, you sign and pay. If you disagree, you have 30 days to request an appeal with the IRS Office of Appeals. The Appeals process is separate from the examination and resolves the majority of disputes without litigation. If Appeals doesn’t resolve the issue, you can petition the U.S. Tax Court.

Your Rights During an Audit

The IRS Taxpayer Bill of Rights (TBOR) gives you specific, enforceable rights throughout the audit process:

Right to be informed — the IRS must explain what it’s examining and why
Right to representation — you can have an enrolled agent, CPA, or attorney represent you; you don’t have to speak to the IRS directly
Right to appeal — every audit determination can be appealed, first to IRS Appeals, then to Tax Court
Right to finality — the IRS generally cannot reopen a closed audit for the same year
Right to privacy — the IRS must follow legal procedures for accessing your information

The most important practical right: you do not have to provide more information than requested. Audit examiners sometimes request additional documents beyond what the notice specifies. You are not obligated to expand the scope voluntarily.

How to Respond to an Audit Letter

For correspondence audits:

Read the notice carefully and identify exactly which line items are being questioned.
Gather documentation for each questioned item — bank statements, receipts, 1099s, written explanations.
Write a brief cover letter that addresses each issue in the order the IRS raised them.
Send via certified mail with return receipt, and keep a copy of everything you send.
Respond by the deadline in the notice. If you need more time, call the number on the notice and request an extension — most are granted without issue.

For office and field audits:

Engage a representative (CPA, enrolled agent, or tax attorney) before the meeting if at all possible. Your representative can attend meetings in your place and is trained to manage the scope of the audit.
Prepare only the documents relevant to the years and items under review — do not volunteer additional information.
Be accurate and consistent. Inconsistencies between your statements and your records create bigger problems than the original issue.
If the examiner asks questions beyond the original scope, your representative can request that any new issues be documented before you respond.

When to Hire a Professional

For a simple correspondence audit — one or two items, straightforward documentation — many taxpayers handle it themselves successfully.

Consider professional representation when:

The audit involves a field agent coming to your home or business
The IRS is questioning self-employment income or business deductions
The audit covers multiple years
You have unreported income from any source
You received a summons (not just a notice)
The proposed tax adjustment is large relative to your ability to pay
You’re uncertain whether your deductions were properly documented

An enrolled agent, CPA, or tax attorney can represent you before the IRS under a Power of Attorney (Form 2848). They speak to the IRS on your behalf, know which documents the IRS is likely to accept, and understand how to navigate the Appeals process if the initial audit doesn’t resolve in your favor.

After the Audit: If You Owe More

If the audit results in additional tax assessed, you have options:

Pay in full — stops interest from accruing further
Set up an installment agreement — estimate your monthly payment
Request penalty abatement — if you have a clean prior compliance history, you may be able to remove the failure-to-pay penalties that have accrued — learn how
Appeal the determination — if you believe the examiner was wrong, CDP hearings and the IRS Office of Appeals give you a formal opportunity to dispute the assessment

Still have questions about IRS Audit Guide: What to Expect and How to Respond?

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