What is standard door width?

The standard width for the average entry door in America is 36". That is not including the frame.

ADA requires 32" clearance when door is open 90 degrees , which results in using a 36" door due to the thickness of the door and projections from the jambs.

Interior doors range in width from 24"-32" in even-number increments. Older homes often have custom widths falling between these numbers. Of these sizes, 30" is the most common in America.