Skip to Content

11 Helpful Tips For Measuring A Door Properly

When measuring for a new door replacement, it’s important that you take the right measurements from the start or you may be wasting your efforts. 

If you are measuring a door for the first time it can be somewhat confusing.

It can also be stressful and frustrating if you take the wrong measurements and end up with a wrong-sized door that doesn’t fit.

The good news is you don’t need to be a pro to measure a door properly, anyone can do it providing you know what to look for and follow a few basic steps.

Here are some helpful tips.

1. Make sure that you have the required tools

To measure a door, you won’t need many tools. But to effectively do the job, you will need a few things. Ensure that you have the following tools:

  • Measuring tape
  • Ladder or step stool
  • Notebook and pencil or a smart device

There are different measuring tools that you can use, but a tape measure will work the best.

A small ladder or step stool will be needed to reach the top of the door frame.

To keep track of your measurements, you will need to write them down on a notepad or notebook.

If you prefer, you can use your phone or smart device to make notes of your measurements.

  1. Before measuring, determine if you are just replacing the door itself or if you are replacing the hinges and door frame. The measurements will be different depending on what you are replacing so this step is crucial. 
  1. If replacing an interior door, it’s important to not just measure the existing door itself. The measurement you take will need to be based on the door frame. Only measuring the door will lead to the wrong measurements. Measuring from the door frame will ensure a better fit. 
  1. If measuring a door slab, you will only need to measure the door itself. Measure the length, width, and height in 3 locations (top, middle, and bottom) and use the largest number. 
  1. Record your numbers using similar units of measurements. Depending on your location, this can vary. Some countries like the UK and Australia use millimeters and some like the USA use inches and feet.  
  1. Buy a bigger door not smaller. If the door size that you require is not available, it’s best to go with the next size up and not down. If the door is slightly larger by a few millimeters, it can generally be sanded or trimmed down to fit perfectly. 
  1. Check to see which way the door opens. Does the door open left or right? This will affect the placement of the hinges and your measurements may be off slightly depending on which way the door swings. 
CHECK OUT  What Is The Correct Height For A Mailbox?
  1. Keep in mind that older style homes may not have perfect door frames and they may be off slightly when it comes to their measurements. The top of the door frame could be different in width than the bottom. There might be indents and imperfections that will affect how precise your measurements are. As mentioned, always use the larger measurements if conflicting. You may end up in a situation with older homes where the door doesn’t fit properly in the frame. In this case, you will need to trim or make slight adjustments to get a proper fit. 
  1. Always allow for clearance due to weather changes. Depending on temperature and time of year, the door and frame can expand and retract which can lead to the door rubbing against the frame and not closing properly. Leaving just a little bit of space and allowing clearance for this will make a big difference. Normally 2 millimeters is a sufficient amount of space.   
  1. If you are replacing a fire door, proper measurements are crucial as most of these doors don’t allow for adjustments like trimming or sanding to get the door to fit properly. Always measure twice and double check the measurements to take note of and ensure you write down the correct numbers. 
  1. Steps for measuring a door

The following steps will ensure that you measure your door properly.

  • Using a measuring tape, measure the width of the door frame. Take 3 measurements from the inside of the door frame and use the largest one. Measure the top, middle, and bottom. Take note of this number.
measure a door properly
  • Measure the height of the door frame starting at the floor to the top of the inside door frame. It’s a good idea to measure both the left and right side of the frame as you might get slightly different numbers. Use the largest one. Take note of this number. You will most likely need a small ladder or footstool for this step. Ask someone to help you as it is much easier to get an accurate measurement with a second person to help. 
Measure a door properly
  • Measure the width of the door that you are replacing and purchase a new one that has the same width. 

What is the standard door size?

Depending on your location the standard door size can vary. In the USA, the most common door size is 3 feet or 36 inches wide and 80 inches tall. The door thickness is 1-⅜ inches. 

In the UK, the standard door size range from 610mm-686mm wide, 1981mm-2040mm tall, and 35mm-40mm thick. 

Sharing is caring!