If you need to purchase a replacement exterior door, please follow the steps below.
Determine if you have a left hand or right hand door.
For a combination (all-in-one) entry door and storm door, measure the width from the outside of the channel on the left to the outside of the channel on the right.
Then the height from the top of the channel to the threshold of the door.
For a replacement door only (without a storm) measure the rough opening of the existing door. Remove the interior trim and measure how big the hole is that exists in the wall of your home.