IWD Iron Door Size & Measuring Guide for Custom Entry Doors
If you're remodeling your home and replacing an existing door, knowing your door's rough opening is essential before ordering a custom door online. Follow this guide and record the measurements below to help you choose the correct door size for the best fit. For IWD pre-hung exterior doors, we generally recommend that the rough opening be at least 1-1/2" wider and 1" taller than the overall frame (unit) size. For example, if your rough opening measures 73-1/2" wide by 97" high, the recommended door size is 72" × 96".
How Our Doors Are Measured
Our doors are pre-hung door systems designed for easy installation. The overall door size is referred to as the net frame size or unit size. Each pre-hung door includes the door panel, header jamb, side jambs, and threshold as one complete unit. The width is measured from the outside edge of the left jamb to the outside edge of the right jamb, while the height is measured from the bottom of the threshold nose to the top of the header jamb.
This overall frame size is the dimension used when selecting the correct rough opening for your project.
What Is The IWD Iron Wrought Doors' Size
When ordering a custom door from IWD Iron Wrought Doors, please provide the correct overall door size (also referred to as the net frame size or unit size). The drawings below illustrate the overall dimensions of common pre-hung iron door configurations, including single doors, double doors, doors with transoms, sidelights, or both.
The height is measured from the bottom of the threshold to the top of the header jamb, while the width is measured from the outside edge of one side jamb to the outside edge of the other. For doors with sidelights and/or a transom, subtracting the overall frame size of the main door leaves the remaining dimensions of the sidelights and transom.
For an accurate quote and a proper fit, please provide the overall dimensions of your complete pre-hung door system.
All IWD custom doors are quoted and manufactured based on the overall frame (unit) dimensions, not the door panel (slab) size.
>> 36"W x 80"H Iron Single Door
>> 68"W x 108"H Iron Double Door
>> 36"W x 108"H Iron Single Door with Transom
The main door unit measures 36"W x 96"H. A 12"H fixed transom is built into the frame above the single door, resulting in an overall frame size of 36"W x 108"H.
>> 74"W x 91"H Steel French Single Door with Double Sidelights
The arched main door unit measures 42"W x 91" H (height measured at the highest point of the arch). It is flanked by two 16" W fixed sidelights. Therefore, the total width is calculated as 42" + 16" + 16" = 74", resulting in an overall frame size of 74"W x 91"H.
>> 144"W x 105.5"H Iron French Double Door with Double Sidelights and Transom
The main door unit measures 74.17"W x 83.61"H. A 21.89"H fixed transom is built into the frame above the double door, and the consoliated unit (74.17"W x 105.5"H) is flanked by two 16"W x 83.61"H sidelights. This brings the overall frame size to 144"W x 105.5"H.
Rough Opening Measuring Guide
Watch this video to learn how to measure for a new pre-hung iron front door.
Measuring the rough opening perfectly is helpful for you to purchase the right door size.
IWD Modern Pivot Door Clear Opening
For an iron pivot door, the pivot mechanism is typically positioned at approximately 1/4 of the door width. As a result, the clear opening width is generally about 3/4 of the total door width.
For example, for a pivot door with an overall width of 68", the estimated clear opening is (3/4 × 68") − 2" (jamb thickness) − 1" (half of the door thickness) ≈ 48".
The example above is based on a typical IWD pivot door configuration and is intended for estimation purposes only. The actual clear opening may vary depending on the pivot hardware, door design, frame dimensions, and installation details. For the most accurate dimensions, please refer to the approved CAD drawings provided by IWD before production.
Door Slab Size <<
The door slab is the actual operating door that does not include any frame. Its width is measured from the inside of the left jamb to the inside of the right jamb. Its height is measured from the bottom of the sill to the inside of the head jamb.
Brick Opening Size <<
The Brick Opening size of the entry door is measured from the exterior side of the house from Brick to Brick.
Measure The Sizes For An Iron Door
Door Slab Size <<
The door slab is the actual operating door that does not include any frame. Its width is measured from the inside of the left jamb to the inside of the right jamb. Its height is measured from the bottom of the sill to the inside of the head jamb.
Rough Opening Size
Determining the rough opening is the quickest and most accurate way to ensure your new pre-hung door fits properly. The rough opening is the framed wall opening that surrounds the door unit and is measured from stud to stud. For the most accurate measurement, remove the interior or exterior casing before measuring. For IWD pre-hung doors, we generally recommend a rough opening that is approximately 1-1/2" wider and 1" taller than the overall frame (unit) size to allow for proper installation and shimming.
Brick Opening Size <<
The Brick Opening size of the entry door is measured from the exterior side of the house from Brick to Brick.
Confirm Your Jamb Size
The jamb size equals the finished wall thickness that your pre-hung door will be installed into, including drywall, sheathing, siding, or other finished wall materials. Choosing the correct jamb size helps ensure a proper fit and reduces the need for jamb extensions or additional trim. For example, if your finished wall thickness is 6", we recommend a 6" jamb. At IWD, the most popular standard jamb sizes are 4-9/16", 6", and 6-9/16", and we can also manufacture custom jamb sizes for any wall thickness.
Follow our tips to accurately measure an arched door
1. Remove the Trim
Accurate measurement of the rough opening requires you to remove the interior molding and measure it from the inside of your home.
2. Measure the Width
Measure the top, middle and bottom width of the door frame. Use the shortest measurement when ordering if you get different dimensions.
3. Measure the Height
Measured from the floor surface or the bottom of the threshold to the peak of the door arch in the center.
4. Measure The Spring Line Height
Measured from the floor surface to the spring point at which the arch begins to curve.
5. Calculate the Arch Height
Write down the arch height; The height of arch = the door frame height(H1) - the spring line height(H2)
Choose The Appropriate Size For Your Barn Door
Barn Door Size Example
84" Tall Opening
Height Size: 84”+2”=86” Your barn door height should be 86” tall.
36" Wide Door
Track Size: 36”+36”-2.36”=69.64” Your barn door track should be 69.64” long.
Make sure you have enough wall space on the side of the opening for the door to open completely.
34" Wide Opening
1. Width Size: 34”+2”=36” Your barn door should be 36” wide if your door is against the wall.
2. Width Size: 34”+4”=38” If your door is in the middle and covers the opening, then your barn door should be 38” wide.
