Measuring Guide

Select the correct size for your door

How Do I Measure My Iron Door?

Ready to add an iron door to your home or business? You’ll likely want to contact a professional (builder or contractor) for measurement and installation, but for a general understanding of how to measure for iron doors, keep reading and you will find it's easy.

Overview for Jamb Size, Rough Opening Size and Door Size

pre-hung iron door size overview for door and rough opening


About jamb size, it is the measurement of the wall thickness that the door unit will be fitting into, this includes any sheetrock or sheathing/siding that is on the outside as well. 4 9/16", 6" and 6 9/16", are the three jamb sizes that most customers choose. Customized jamb size is also acceptable.

Rough opening size refers to the size of the opening in a wall that is created to accommodate a door. The size is typically larger than the actual size of the door to allow leaving space to install the door.

So, how do you finalize your door size if knowing the rough opening size?
We will recommend the rough opening is at least about 1" wider than the frame size/ unit size and about 1/2" taller.
For example:
Rough Opening Size: 73"x96 1/2" → Door Size: 72"x96"


The size of iron door is called net frame size or unit size. It is a whole door system that consists of a header jamb, side jambs, and a threshold.

Here is the way to measure the door:
1. Measure the height of the door from the bottom of the door threshold to the top of the door jamb.

2. Measure the width of the door from the edge of one side of the door jamb to the edge of another side.

As below drawing shown, the overall door size is 72"x96", and you will find the size on our finished door.