By George House/04,Sep,2025
French doors are the black cocktail dress of house style—chic, always appropriate, and never obsolete. They instantly illuminate a room, beautifully set off outdoor views, and give that “wow” without even trying too hard.
But before you fall in love with a pair, you’ve got to know your sizes. Too small and they look awkward, too large and they may not even function properly. That’s why knowing the standard French door sizes is the real secret to pulling off the look.
What Are French Doors?
French doors are identified by their full-length glass panels, usually separated into smaller panes (called “lites”) by bars known as muntins, often in a grid pattern. Grid can be true-divided or simulated (grilles between glass for easy cleaning).
This design became widespread in 17th-century France during the early Baroque era (hence the name), although the inspiration comes from even earlier Italian architecture. These doors were essentially made to resemble windows, which is why they’re so good at visually connecting indoor and outdoor spaces.
You’ll often hear different types of French doors.
- Single French door (called a leaf): Often used for interior rooms like home offices, studies, or balconies where you want elegance but don’t have space for two swinging doors.
- Double French doors: The iconic two leaves—one leaf is typically active (operational), while the other is inactive (or fixed), secured by a bolt at the top and bottom. Common for exterior use—patio doors, backyard access, or even as a dramatic entrance, such as between a living room and a sunroom.
There are also sliding French doors, pivot French doors, or French doors with a transom, suitable for different spaces, sizes, and functions.
Standard French Door Sizes
There are a few “standard” French door sizes that you can almost find everywhere. However, that “standard” actually isn’t always universal. It often comes with some wiggle room depending on factors, such as:
1# Regional Codes
At some places, local building codes prescribe the dimensions of certain doors of a house or commercial establishment, based on where and what type of construction it is.
In the U.S., for example, the International Residential Code (IRC) mandates that one of the main entry doors of a home be no less than 36 inches wide and 80 inches tall. That’s why exterior French doors generally stick close to these numbers. Meanwhile, interior French doors might be slimmer, since they aren’t expected to handle the same level of foot traffic or security.
2# Style vs. Size Availability
Manufacturers also tie certain styles to specific sizes. For instance, slim, tall French doors with divided glass panes tend to come in narrower widths due to the structure of their frames. Wide patio-style sliding French doors, on the other hand, typically come in larger, standardized double-leaf sets.
Below are the common standard sizes you’ll find when shopping for French doors(both single and double).
| Height (inches) | Single French Door Width (inches) | Double French Door Width (inches) | Depth/Thickness (inches) |
| 80″ | 30″ | 60″ (2 x 30″) | 1 3/8″ |
| 80″ | 32″ | 64″ (2 x 32″) | 1 3/8″ |
| 80″ | 36″ | 72″ (2 x 36″) | 1 3/8″ |
| 96″ | 48″ | 96″ (2 x 30″) | 1 3/4″ – 2″ |
| 96″ | 60″ | 120″ (2 x 36″) | 1 3/4″ – 2″ |
Thicker doors feel sturdier, insulate better, and are often required for exterior use.
| Standard French Door Thickness (inches) | Common Use Case |
| 1 3/8″ | Interior French doors |
| 1 3/4″ | Exterior French doors (residential) |
| 2 1/4″ | Heavy-duty or commercial use |
How to Measure French Door Size According to Rough Opening?
Even the most gorgeous French doors will be hell if they don’t fit into the frame. The key is to make sure it’s plumb enough for a tight seal, but also have a margin for a smooth operation. Here’s how to measure your door like a pro:
Step 1: Measure the Rough Opening Width:
Measure the horizontal distance between the top, middle, and bottom exposed wooden framing (the studs) at the opening. Use the smallest number—because the door dimensions aren’t perfect up to millimeters.
Step 2: Measure the Rough Opening Height:
Measure the vertical distance from the top of the opening down to the sill (or subfloor) at the left, center, and right. Once again, use the smallest reading.
Step 3: Check for Square:
Measure diagonally from top left to bottom right, and from top right to bottom left. If the two measurements don’t match, your opening is out of square—a frequent occurrence in older homes. In this case, the door will need adjustments during installation.
Step 4: Account for Trim and Frame
Now that you have approximate opening sizes, keep in mind that the door unit itself (the slab(s)) will be 0.5-1 inch smaller in width (per leaf) and up to 2.5 inches shorter than these readings. This allowance is needed for shimming, leveling, and good insulation around the frame. The extra height also accommodates the head gap and sill, ensuring the doors swing or slide smoothly.
Here’s how the actual calculations may look:
| Door Type | Nominal Door Size (W x H) | Actual Door Unit Size (approx.) | Recommended Rough Opening (W x H) |
| Single | 32″ x 80″ | 31.5″ x 78″ | 32.5″ x 80.5″ |
| 36″ x 80″ | 35.5″ x 78″ | 36.5″ x 80.5″ | |
| 48″ x 80″ | 47″ x 78″ | 48.5″ x 80.5″ | |
| Double | 64″ (2 x 32″) x 80″ | 63″ x 78″ | 65″ x 80.5″ |
| 72″ (2 x 36″) x 80″ | 71″ x 78″ | 73″ x 80.5″ | |
| 96″ (2 x 48″) x 80″ | 95″ x 78″ | 97″ x 80.5″ | |
| 120″ (2 x 60″) x 80″ | 119″ x 78″ | 121″ x 80.5″ |
If your heart is set on a specific style but it doesn’t come in your needed size, or if your entrance really does qualify as one-of-a-kind, you can also have custom French doors made.
Recognised manufacturers like George Group offer the option, with some premium cost. But this route gives you the most freedom of style, material, and size. Plus, it comes in particularly handy if you desire something unique, like arched openings or wider frames.
Fitting Tips and Installation Planning
If you’re in touch with the tools, you may be able to fit French doors yourself—particularly interior doors. However, exterior doors or non-standard sizes are usually worth paying someone to do. They’ll guarantee accurate alignment, weatherproofing, and security.
Key things to remember:
- A 36″ door will require a minimum of 36″ of clearance to open without bumping against light switches, furniture, or walls.
- Think about how it will ride with your floor. Will it sweep rugs or transitions? Will the bottom rail dig into the hardwood on its way?
- Be ready to spend a lot of time using shims to get the new square door frame into an unsquare hole.
- To keep drafts and air leaks out, seal the gap between the new frame and rough opening with high-grade expanding foam insulation.
- After cutting the foam, run a bead of exterior-grade silicone caulk along the outside on all sides of the frame where it hits your home’s siding to provide a water-tight seal.
Conclusion
French door sizes are fairly consistent until they’re not—varied by regional codes, your home’s age, and your personal style. The most important step is measuring your space accurately and understanding how the door will fit in your home.
If you’re ready to add French doors to your home or business, check out a vast catalogue of both standard and custom options by George Group. They also provide professional consultations to make sure your doors don’t just look good—but also fit perfectly.
