What size landing is required outside an exterior door, and how far can the floor drop at the threshold?

Exterior doors need a landing at least as wide as the door and 36 inches deep in the direction of travel; at the required egress door the floor can be no more than 1.5 inches below the threshold (IRC R311.3).

There must be a landing or floor on each side of every exterior door. Each landing has to be at least as wide as the door it serves and provide a minimum of 36 inches measured in the direction of travel (R311.3).

At the required egress (main exit) door, the landing or floor cannot be more than 1.5 inches lower than the top of the threshold (R311.3.1).

For other exterior doors, a larger step down — up to 7-3/4 inches — is allowed only where the door does not swing out over the landing (R311.3.2).