An income tax audit is when the IRS examines your tax return to verify that the information you reported is accurate and complete.

The IRS does not audit every return. They select returns based on patterns in the data, random sampling, or specific red flags — such as unusually high deductions, business losses, or cash-heavy income. When your return is chosen, the IRS sends you a notice by mail. The notice tells you which items they want to examine, what documents to bring or send, and whether the audit will happen by mail, in person at an IRS office, or at your tax preparer's location.

An audit does not automatically mean you owe money or committed fraud. Many audits result in no change to your tax bill. Others result in a small adjustment. The IRS is checking whether your numbers match your records — receipts, bank statements, invoices, and other proof of income and deductions.

Key Takeaways

  • The IRS notifies you by mail if your return is selected for audit; you will not receive a phone call or email from the IRS initiating an audit.
  • The notice specifies which tax year, which items on your return, and what documents the IRS wants to see.
  • You can respond by mail, meet in person, or have a tax professional represent you without attending yourself.
  • Most audits are resolved within a few months, though complex cases can take longer.
  • If you disagree with the IRS findings, you have the right to appeal before paying any additional tax.

Types of audits: mail, office, and field

A correspondence audit happens entirely by mail. The IRS sends you a letter asking for specific documents — a receipt for a charitable donation, proof of business expenses, or a mortgage statement. You gather the documents, send them to the address in the notice, and wait for a response. This is the most common type and usually the simplest.

An office audit requires you to visit an IRS office in your area on a scheduled date. You bring the documents the notice requests. An IRS agent reviews them with you, asks questions, and may ask for additional records on the spot. You can bring a tax preparer, accountant, or attorney to represent you, and you do not have to attend if someone else goes on your behalf.

A field audit is the least common. The IRS agent visits your home, business, or your tax preparer's office. This type is typically used for business returns with complex issues, large deductions, or suspected underreporting of income. The process is similar to an office audit but takes place at your location.

What triggers an audit

The IRS uses computer systems to score returns and flag those with unusual patterns. High deductions relative to income — such as claiming $50,000 in business expenses on $60,000 of self-employment income — can trigger review. Large charitable donations, significant business losses, home office deductions, and cash-based businesses are audited more often than average.

Math errors and inconsistencies between your return and documents the IRS already has also prompt audits. If you report $40,000 in W-2 income but your employer reports $45,000, the IRS will notice. Unreported income from a 1099 form, a K-1 from a partnership, or a brokerage statement can also cause the IRS to examine your return.

Random selection happens too. The IRS audits a small percentage of returns at every income level straightforward to maintain compliance. Being selected does not suggest wrongdoing.

What documents to gather before your audit

The audit notice will list the specific items the IRS wants to examine. Gather originals or clear copies of anything that supports those items. For income, bring W-2 forms, 1099 forms, bank statements, and business records. For deductions, bring receipts, invoices, credit card statements, and cancelled checks.

If the audit covers business expenses, organize records by category — office supplies, utilities, vehicle mileage, meals, travel. Keep a log showing dates, amounts, and what each expense was for. If you no longer have original receipts but have bank or credit card statements showing the transaction, those can work as backup proof.

Bring your tax return itself and any worksheets you used to calculate deductions. If a tax preparer or accountant prepared your return, ask them for copies of their work papers. Do not bring documents the notice does not ask for; stick to what they requested.

How long an audit takes

A correspondence audit typically takes four to eight weeks from the time you mail your documents. An office or field audit can take anywhere from one to three months, depending on how quickly you provide documents and how complex the issues are. Some audits are resolved in a single meeting; others require follow-up requests for additional records.

The IRS has a legal time limit to audit your return. For most returns, that limit is three years from the date you filed. If the IRS suspects substantial underreporting of income — generally 25 percent or more — the limit extends to six years. If fraud is suspected, there is no time limit, though this is rare.

What happens after the audit

After reviewing your documents, the IRS sends you a letter with the results. If no changes are made, the letter says your return is accepted as filed. If the IRS found errors or disallowed deductions, the letter explains what changed and how much additional tax, if any, you owe.

If you owe money, the letter includes instructions for payment. You can pay in full, request a payment plan, or ask for more time to pay. If you disagree with the findings, you have the right to appeal. The letter will explain how to request an appeal and the important date to do so — usually 30 days.

An appeal goes to an independent IRS office separate from the one that conducted the audit. An appeals officer reviews the case and your arguments. Many cases are settled at the appeals stage without going to court.

Representation during an audit

You do not have to represent yourself. You can hire a tax professional — a CPA, enrolled agent, or tax attorney — to handle the audit on your behalf. The IRS will communicate with your representative instead of you. Your representative can attend meetings, request documents, and negotiate with the IRS.

If you choose representation, give your representative a power of attorney form so the IRS will recognize their authority to act for you. This form is available on the IRS website. Your representative can often resolve issues faster because they understand tax law and IRS procedures.

Frequently Asked Questions

Can the IRS call me about an audit?

No. The IRS always initiates an audit by mail. If someone calls claiming to be from the IRS about an audit, it is a scam. Hang up and do not provide any information. You can contact the IRS directly using the phone number on your tax return or the IRS website to verify whether you are actually under audit.

What if I cannot find a receipt for a deduction?

Bank statements, credit card statements, and cancelled checks can substitute for receipts if they show the date, amount, and payee. If you have no documentation at all, the IRS will likely disallow that deduction. For future audits, keep receipts for at least three years.

Do I have to pay the additional tax while I appeal?

No. You can request an appeal without paying first. However, if you do not pay and the appeal is denied, you will owe the tax plus interest calculated from the original due date. Interest accrues while the appeal is pending.

What if the audit finds I overpaid my taxes?

The IRS will issue a refund for the overpayment. The refund is processed like any other refund — by check or direct deposit, depending on how you filed. This can take several weeks.

Can an audit lead to criminal charges?

Criminal prosecution is extremely rare. Most audits are civil matters. Criminal charges require evidence of intentional fraud, not straightforward mistakes or aggressive deductions. If the IRS suspects criminal activity, they typically refer the case to the Criminal Investigation division, and you would be notified separately.