What is the audit rate? Q.What is the audit rate? A.The audit rate is the percent of tax returns filed for a tax year that are ultimately examined by the IRS. About 153.9 million individual tax returns were filed based on 2018 income, but only about 520,000 of those returns were audited—an overall audit rate of 0.3 percent. Audit rates are generally highest for high-income taxpayers, taxpayers with business income, large corporations, and earned income tax credit claimants. Read more about What is the audit rate?