An in-person IRS audit costs the agency about $6,418 on average, according to research analyzing internal IRS accounting data.1Policy Impacts. A Welfare Analysis of Tax Audits Across the Income Distribution A mail audit costs a small fraction of that. A multi-year examination of a wealthy taxpayer or a large corporation can run into the tens of thousands. The IRS doesn’t publish a single per-audit price tag because the number depends almost entirely on what kind of return is being examined and how complicated the issues turn out to be.
Why the Average Depends on the Type of Audit
The IRS runs audits three different ways, and the cost gap between them is the reason any single “average” figure is misleading without context. The agency itself sorts examinations into audits conducted by mail and audits conducted through in-person interview, with the in-person category split between office and field locations.2Internal Revenue Service. IRS Audits
A correspondence audit is a letter asking for documentation on a specific line item, like a charitable deduction or education credit. You respond by mail. These are largely automated, involve minimal staff time, and make up the vast majority of all audits. They are by far the cheapest for the IRS to run.
An office audit brings you or your representative into a local IRS office to meet with a Tax Compliance Officer. These focus on returns with more moving parts, often small business owners or filers with a Schedule C, where a sit-down review of receipts and records is required.
A field audit sends a Revenue Agent to your home, business, or accountant’s office. These are reserved for the most complex cases involving large corporations, partnerships, or high-income individuals, and they consume the most IRS resources by a wide margin.
What the $6,418 Actually Pays For
Economists studying IRS administrative records estimated the average in-person audit of an individual taxpayer at $6,418. Only about 19% of that spending goes directly to the wages of the enforcement officers working the case.1Policy Impacts. A Welfare Analysis of Tax Audits Across the Income Distribution The rest covers everything the agency needs to keep the examination running.
Personnel costs still dominate, just broadly defined. That includes not only the Revenue Agent or Tax Compliance Officer assigned to your case, but their managers, support staff, and anyone who reviews the work product. The IRS also carries significant overhead: field offices, secure document storage, and the technology infrastructure behind its case management systems. Direct operational expenses fill in the rest, including travel for field examiners, printing and mailing official notices, and the computing power behind automated document matching.
Correspondence audits sit far below that in-person average because they run through largely automated systems with minimal human review. No publicly available figure pins down the exact per-case cost, but a mail audit might require only a few hours of staff time to process the response and close the file.
Why Some Audits Cost Far More
The type of return under examination is the single biggest cost driver. A W-2 wage earner with straightforward income and a questionable deduction is the cheapest audit the IRS runs. Third-party reporting already confirms most of the numbers, the documentation is simple, and the examination usually wraps through correspondence.
Small business owners and self-employed filers cost more. Their returns involve business expenses, vehicle deductions, home office claims, and sometimes inventory or depreciation schedules. These often require an office or field audit where a Revenue Agent works through actual books and records.
The most expensive audits target high-net-worth individuals and large corporations, and they can stretch over multiple tax years. They also require specialists. The IRS employs senior economists to resolve complex transfer-pricing disputes, general engineers who apply valuation principles to tax matters, and competent authority analysts who serve as experts on tax treaty issues and international allocations.3Internal Revenue Service. Large Business and International – IRS Careers When foreign bank accounts, multi-layered partnership structures, or cross-border transactions are in play, these specialists can bill hundreds of hours to a single case.
Even within the same taxpayer category, costs vary based on how the audit unfolds. Taxpayer cooperation matters more than most people realize. When someone ignores notices, refuses to produce records, or forces the IRS to issue a summons to compel document production, the administrative and legal machinery gets expensive fast. Each escalation adds staff hours, supervisor review, and potential involvement from IRS counsel.
If a proposed adjustment is disputed, the case can move to the IRS Independent Office of Appeals. Before that, the IRS offers a Fast Track Settlement program where an independent mediator tries to help both sides reach agreement. The agency aims to resolve these mediations within 60 days for individual taxpayers and within 120 days for large businesses or those with international interests.4Internal Revenue Service. Fast Track
When neither mediation nor appeals resolves the dispute, the taxpayer can petition the U.S. Tax Court. At that point the IRS needs attorneys from the Office of Chief Counsel, possible expert witnesses, and extensive support staff. Litigation is the single biggest cost multiplier in the entire audit process, which is precisely why the IRS prefers to settle before it gets there.
What the IRS Gets Back
The IRS doesn’t view audit costs purely as expenses. The agency measures enforcement through return on investment, comparing what it spends on examinations against what it collects.
Research using IRS data found that the average audit collects $13,930 in additional revenue, which is 2.2 times the total cost of the examination. That overall figure masks significant variation across income levels. Higher-income audits cost more to run, but those higher costs are more than offset by the revenue they produce. Audits of the top 0.1% of earners generate a return of 6.29 to 1, meaning every dollar the IRS spends examining these returns yields more than six dollars back.1Policy Impacts. A Welfare Analysis of Tax Audits Across the Income Distribution
The value stretches well past the immediate tax bill. People who have been audited pay more in taxes for at least 10 years afterward, and the subsequent revenue generated is roughly three times greater than the amount collected during the initial audit.1Policy Impacts. A Welfare Analysis of Tax Audits Across the Income Distribution Deterrence spreads outward too. An active enforcement presence discourages underreporting across the broader taxpayer population, which is one reason the IRS’s estimated annual gross tax gap still sits at $696 billion.5Internal Revenue Service. The Tax Gap
How Funding Cuts Are Changing the Math
The cost-per-audit figures above sit inside a funding picture that has shifted sharply in the past few years. The Inflation Reduction Act of 2022 originally provided approximately $79.4 billion in supplemental IRS funding, much of it earmarked for enforcement. Congress has since rescinded $41.8 billion of that total through three successive legislative actions, reducing available IRA funding to $37.6 billion as of March 2025.6Treasury Inspector General for Tax Administration. The IRS’s Inflation Reduction Act Spending Through March 31, 2025 All of those rescissions came from the enforcement stream.
The practical effect on audit costs is real. With less funding, the IRS has less capacity to conduct the expensive but high-return field audits of wealthy taxpayers and large corporations. The agency’s growing use of artificial intelligence and automated data matching to select returns is partly an efficiency response, letting software do more of the screening work that human reviewers once handled. The systems compare filed returns against W-2s, 1099s, payroll records, bank data, and digital asset reporting forms to flag discrepancies before a case ever lands on an examiner’s desk. Whether the remaining funding is enough to sustain the enforcement presence that drives long-term compliance is still an open question.