How to Measure a Door in 5 Easy Steps


How to Measure A Door in 5 Easy Steps

Have you ever wondered if measuring a door is as straightforward as it seems?

It actually may be a bit more intricate than you realize, and these measurements can affect both the fit and function of the door within your wall space, no matter if it’s an interior or exterior door. Understanding the correct dimensions goes beyond just the width and height; it involves a keen eye for detail and precision, or at least training on how to do it properly. Luckily, most house doors follow nominal dimensions, meaning they are standard sizes and easy to remember.

By following a few simple steps, you can ensure that the door measurements for your door slab and door jamb are accurate for your unique scenario.

Read the rest of this article to uncover the essential techniques for measuring a door effectively.

1. Gather Necessary Tools


To measure a door accurately, first gather a tape measure, a pencil, and something to write on like a notepad, because these tools are essential for obtaining precise measurements. The tape measure allows you to determine the height, width, and depth of the door, ensuring accurate dimensions for any replacements or modifications. Having a pencil and writing surface on hand enables you to mark down the measurements as you go, preventing any confusion or mistakes.

Before starting, make sure the tape measure is operating properly, and the pencil is sharp for clear markings. By having these simple tools ready, you’ll streamline the measuring process and ensure the measurements are correct for any future door-related projects. So, grab your tools, and let’s get started!

2. Measure Door Width


If you’re all set with your tape measure, pencil, and notepad, the first step in measuring a door is determining its width. To do this, position yourself on one side of the door frame. Extend the tape measure horizontally from one side to the other, taking note of the measurement in inches.

Make sure to measure at three different heights: top, middle, and bottom. The reason for this is that door frames can sometimes be uneven (if this is the case, you’ll definitely want to call a local door company to get it fixed so your door can seal properly). Once you have these three measurements, record the smallest one.

This smallest width measurement ensures that the door you purchase will fit effortlessly into the existing frame. Again, if your frame is not aligned, you’re going to have sealing issues, so you’ll want to call a professional in that case. Remember that accuracy is key when measuring the width of a door.

The most common widths for residential doors are typically 28 inches, 30 inches, 32 inches, and 36 inches. These sizes are commonly used for interior and exterior doors in residential homes.

3. Measure Door Height


When measuring the height of a door, ensure your tape measure is positioned vertically along the side of the door frame. Start at the very top of the door frame and extend the tape measure all the way down to the floor. Make sure the tape measure is straight and not slanting in any way to get an accurate measurement.

Take note of the measurement in feet and inches, rounding up to the nearest eighth of an inch if needed. It’s crucial to measure the height at multiple points along the door to account for any irregularities. Once you have your measurements, note them down carefully to ensure you have the correct door height for any future door-related endeavors.

Standard residential door heights typically range from 80 inches (6 feet 8 inches) to 96 inches (8 feet). Some common heights for residential doors include:

  1. The most common is 80 inches (6 feet 8 inches)
  1. The second most common is 96 inches (8 feet)
  2. Rarely, you’ll see 84 inches (7 feet)

These are the most common door heights for residential use, but custom sizes are also available to fit specific needs and preferences.

4. Determine Door Thickness


Measure the thickness of a door by placing the tape measure horizontally across the width (inside edge) of the door. Ensure the tape measure is positioned at the edge of the door to get an accurate measurement. Look for the thickest part of the door, as some doors (especially entry doors) may have panels or designs that affect the thickness.

Once you have the measurement, note it down for reference. Standard interior doors typically have a thickness of 1 3/8 inches, while exterior doors are usually thicker, ranging from 1 3/4 to 2 inches.

Knowing the thickness of the door is crucial for selecting the right hardware, and ensuring a proper fit during installations or replacements, you don’t want to get the wrong size door.

5. Check for Squareness


To assess the squareness of a door, position a carpenter’s square against the corners to check for alignment. Place the square in the upper corners of the door, ensuring it sits flush against both edges. If the door is square, the square’s arms should align perfectly with the door edges, forming a 90-degree angle. Check both upper corners (left arm and right arm) to confirm consistency.

Next, move the square to the lower corners of the door and repeat the process. If the door is out of square, the arms of the square won’t align properly with the edges, indicating misalignment. Correct any discrepancies before proceeding with further measurements to ensure accurate dimensions for your door replacement or installation.

Unless you’re extremely experienced, we recommend employing a local professional door contractor to help you fix your doors alignment, especially if it’s an entry door like double doors, as you can cause more problems and headaches unnecessarily if it’s not done the right way the first time.

Frequently Asked Questions

Can I Use a Regular Measuring Tape or Do I Need a Specific Type of Tool to Measure a Door Accurately?

You can use a regular measuring tape to measure a door accurately.

Make sure to simply measure the height, width, and depth to get the correct dimensions.

Take into account any trim or molding for precise measurements.

How Do I Account for Any Door Trim or Molding When Measuring the Width and Height of a Door?

When measuring a door, remember to account for any trim pieces, hinges or molding (including each bottom corner and top corner, both left hand and right hand) by adding their dimensions to the width of the door and height measurements to get an accurate size and to make sure everything will fit properly when replacing parts (or all) of your door. Adding in trim pieces and molding will give you the largest measurement possible.

Use a regular measuring tape for this task.

Is It Necessary to Measure Both the Inside and Outside of the Door Frame to Ensure Accuracy?

When measuring a door, it’s essential to measure both the inside and outside of the door frame, especially if you’re going to replace or install a new door. This ensures accuracy and accounts for any variations that may exist.

Taking both measurements will help you get the right fit.

What Is the Standard Clearance Needed for a Door to Swing Open and Close Properly?

To ensure your door swings properly, allow for a standard clearance of about 2 inches on the hinge side and 1/2 inch on the latch side.

This space gives your door room to open and close smoothly, no matter the swing direction.

How Do I Measure for a Pre-Hung Door Versus a Slab Door?

To measure for a prehung door, include the frame width, meaning the entire door unit, including the door sweep and interior trim.

Measure the door via the width and height of the rough opening for a slab door.

Ensure correct measurements for a perfect fit.

Follow manufacturer guidelines to get an accurate door size.


Now that you have gathered your tools and measured the width, height, thickness, and squareness of your door, you’re ready to proceed with any necessary repair or replacement door.

Remember to double-check your measurements for accuracy before making any decisions on changing your existing door.

With these simple steps, you can ensure that your new door will fit perfectly and enhance the overall look of your space.

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