Steel French Door Sizes: The Complete Measuring & Buying Guide

Ordering a steel French door is exciting, until you look at the size chart. Suddenly you see numbers like 36x80, 60x96, or 72x80, and no one warned you that "French doors" are actually a whole family of different sizes. Ordering the wrong one will either result in you having to return the product or have the frame rebuilt - neither of which is fun. 

The good news is, this sizing system makes a lot of sense once you know what you're looking at. Below is everything you need to know: standard single and double steel French door sizes, how to properly measure your door opening, and those little things that often confuse people.

What the Numbers Actually Mean

Each steel French door is measured in inches as width x height, and this refers to the door itself - not the opening in your wall. A 36x80 door is 36 inches wide and 80 inches tall. Pretty simple.

Steel French doors come in two configurations:

Single Door — A single panel with glass, used as a simple entryway or side and back doors.

Double Door — Two identical panels that join in the middle to create a wider, more attractive entryway.

Both types of doors are available in a few specific widths and two common heights. Most suppliers, including USA Builders Depot, stock a variety of glass styles and finishes, so if you want something custom-looking, it’s easy to estimate the size.

Standard Single Steel French Door Sizes

Determining the size of a single door is easy, as you only have to think about one panel.

36x80 single steel French doors are the most common size in American homes. They fit into most existing frames without causing structural damage, making them a safe option for direct replacement. The 36x96 size is more suitable for new construction or renovations where you want a taller entryway — especially in all-glass or multi-panel designs.

Standard Double Steel French Door Sizes

Many people are confused about double doors because the listed size is the combined width of the two panels, not the single width of any one panel.

A 60x80 double steel door is two 30-inch panels placed side by side. A 72x96 door uses two 36-inch panels and gives you a full six-foot entryway with extra height. 

Doors up to 60x120 are available for larger entryways or commercial projects — typically found in the main entrance of a luxury home or boutique store. The same logic applies to sliding patio doors: The listed size is for the entire unit, not half of it.

How to Measure Before You Order

Before ordering any size steel French door, grab a tape measure and take these measurements:

1. Width — Measure the top, middle, and bottom of the opening. Use the smallest number. Older frames are almost never perfectly straight.

2. Height — Measure from the floor to the top of both sides of the frame. Again, use the smallest number.

3. Wall Depth — Check the depth of the jamb, especially on pre-hung units, to ensure the frame sits flush with your wall.

4. Opening Direction — Will it open to the left or right, inward or outward. Make sure this is correct before ordering.

5. Squareness Test — Measure at an angle from one corner to the other on both sides.

If the difference between these two numbers is more than a quarter of an inch, your opening is not square and needs to be corrected before installation. 

If you are replacing an older door, measuring the existing slab can be a good alternative test. Steel French door sizes are determined based on standard slab sizes, so if the old door is a whole number like 36x80, you're probably dealing with a standard rough opening.

Confirm the complete frame before framing the rough opening

The nominal door size and the required rough opening are not necessarily the same measurement. The correct rough opening depends on the overall outside dimensions of the complete frame assembly, the installation system, and the conditions of the wall opening.

Before framing or ordering, confirm the exact USABD product/frame specification for the door configuration being used. Measure the prepared opening in multiple locations, check it for plumb, level, and square, and coordinate the threshold with the finished-floor elevation.

Do not rely on a universal “add two inches” rule for final framing. Single doors, double doors, sidelites, transoms, and different frame systems can require different overall opening dimensions.

For a project-specific opening, use the technical drawing for the exact door assembly or contact USABD before framing.

Get the Steel French Door Size Right, the First Time

Once you know the difference between slab size and rough opening, and you've taken careful measurements, steel French door sizes aren't complicated. The choice between single and double comes down to your opening width and the look you're after.

USA Builders Depot carries steel French doors in all the standard sizes above — from 32x80 singles to wide double configurations — along with multiple glass patterns and finish options. If your opening is non-standard, custom sizing is available so you don't have to force the wrong door into an unconventional space. 

Browse the full steel door collection to compare options side by side, or contact the team for help matching the right door to your exact opening.