How to Measure a Door the Right Way in 7 Easy Steps
All you need to measure up to the task
- Pencil
- Tape measure
- Pry bar (optional)
- Hammer (optional)
- Paper
- Putty knife (optional)
Sometimes, the only thing standing between you and a new door is its measurements. Learning how to measure a door is a crucial skill when you’re ready to replace your current one. In this guide, we’ll walk you through the steps you need to take to measure your door, so you’re one step closer to ordering that beautiful hunk of wood you’ve been eyeing.
Accurate door measurements are essential for a successful installation. Height and width matter, but jamb width, door swing, and clearance are also key. A professional installer can assess these details and recommend the best solutions.
Draw a Rough Sketch of Your Door
Photo: Dougal Waters / DigitalVision / Getty ImagesBefore you find any measurements, you’ll need somewhere to house them. Plus, it’s much easier to remember all those numbers when you have them written down somewhere. Grab a pencil and paper, and sketch out your door to see all of its dimensions.
Determine Your Door’s Swing and Handing
While it might not be a measurement, your door’s swing and handing are equally important in getting the measurements for a replacement or new door. Your door’s handing refers to whether it’s a left-handed or a right-handed door, and its swing is based on whether it swings out or swings in.
Stand outside of your home or the room you’re trying to enter. Place your back against the hinged side of your door and see which hand is closest to the door knob. If your left hand is closer, it’s a left-handed door, and vice versa. Now, open your door. If the door opens towards you, it’s an outswing door, and if it opens away from you, inside the room, it’s an inswing door. Jot down your findings on your sketch for future reference.
Remove Interior Casing
Photo: jopstock / Moment / Getty ImagesIf you need to replace your entire door system, you’ll need to remove the interior casing, also known as molding, to see your rough opening, which is where your new door will go. Use your putty knife to remove caulk or sealant between the casing and wall to prevent damaging both. Then, use your pry bar to pry it away from your wall carefully.
Measure its Width
If you’re only replacing the door slab, measure the width of it in three places: top, middle, and bottom. If you get three different numbers, use the shortest measurement as its width. If you need to find the size for sliding glass doors, door systems, or double doors, you’ll also need to measure the rough opening from one end of the frame to the opposite end in three places.
Measure its Height
To get the door slab’s height, measure it on the left, middle, and right and write down the shortest number. For the rough opening, you’ll need to measure from the top of the header to the floor in those same places.
Measure the Thickness of the Door and Jamb
Photo: yamasan / Adobe StockWhen learning how to measure for a door replacement, you need to measure the thickness of your door slab to ensure a proper fit. You’ll also measure the jamb’s thickness from end to end, excluding your door casing size from your measurements.
Replace Your Interior Casing
After you have all of your measurements, it’s time to replace your interior casing if you need to remove it. Reposition your casing and use a hammer to put the nails back in their holes.
Measuring a Door: DIY vs. Hiring a Pro
If you’re confident you can get accurate measurements and purchase the correct size door the first time, this is an easy DIY that you can complete in no time. But if you’re not sure how to accurately measure a door size, or if you’d rather let someone else handle this, then contact a pro. Your local door installer can quickly jot down your door measurements, assess your frame’s condition, and install your new door for you. The cost to install a door is $1,120 on average.
Frequently Asked Questions
Standard door sizes can vary depending on the type of door you want. Typically, the standard height is 80 inches, while the standard width for an interior door can be 32 inches, and 36 inches for an exterior door. Other common door heights are 84 inches and 96 inches. Doors can also be 18- to 42-inches wide.
Yes, if your frame is in good condition, you can purchase just a door slab. A door slab is a hollow core or solid wood door without hardware like a frame or hinges. While some slabs may come with the cutout for the door hardware, most don't, which means you’ll have to handle that yourself. On the other hand, if your frame isn’t in good condition, a prehung door, which comes with a frame, hinges, and door hardware cutouts, is worth considering.
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