Providing the documentation to satisfy a tax audit could take as little as a few minutes, or the audit process could drag out for months or years.
When the IRS initially contacts you about an audit, it will include a deadline for you to respond to the document request. You sometimes can submit this information by mail in just a few minutes. Other times, you will have to meet with IRS agents in person, and you could end up having multiple meetings that may stretch over months.
Ultimately, the length of the audit depends on things like the complexity of the return, the type of information requested, and the availability of the taxpayer to attend meetings. Many times, hiring a tax attorney to help with the audit can expedite the process, because the tax attorney can handle the complexities that cause the process to take a long time.