IRS phone lines are typically very busy during the January - April filing season.
Before you wait on hold, try these IRS self-help options below (if you haven't already):
If you must call, make sure the IRS is the right agency to handle your request. For telephone assistance, see IRS Telephone Assistance. Individuals can call (800) 829-1040, Monday - Friday, 7:00 AM - 7:00 PM local time.