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Easiest Way to Measure for a Door Replacement

how to measure a door for replacement

Are you tired of dealing with that sticking, drafty, or just outdated door? Regardless of why you’re looking for a replacement, you’ll need to measure the current door for a perfect fit. Don’t worry, though – it’s easier than you might think!

With just a few simple tools and tips, you’ll be on your way to a seamless replacement in no time. We’ll walk through the measuring process, share recommended maintenance, and make sure you know when to bring in an expert.

Tools You’ll Need

Having the right tools is essential to accurately measure your existing door or the replacement. Don’t worry, you don’t need anything fancy – just a few basic items you probably already have around the house:

  • A strong metal tape measure (it won’t bend or stretch when you extend it)
  • A pencil and paper to write down your measurements
  • A level (not required, but it can help make sure your door frame is straight)
Some of the tools that should be on hand to measure a door for replacement.

Step-by-Step Guide to Measuring Your Door

Now that you have your tools ready, it’s time to start measuring. Follow these simple steps to get the most accurate measurements for your new door:

1)Measure the width of your door frame at three points – the top, middle, and bottom. Place your tape measure at each point, going from one side of the frame to the other, and write down the measurements. If they’re slightly different, use the smallest one when ordering your replacement door to ensure a snug fit.

2) Measure the height of your door frame. Record the distance from the floor to the top of the frame on both the left and right sides. If the measurements are different, use the larger one to avoid any issues with the new door. This will also help you determine if you need to make any adjustments during installation.

3) Measure the thickness of your current door. Open the door and place your tape measure on the edge, extending it from the front of the door to the back. Standard interior doors are typically 1 3/8″ thick, while exterior doors are usually 1 3/4″ thick. Make sure to choose a replacement door with the same thickness to ensure it fits your existing frame and hardware.

Considerations for Special Cases

  • If your door frame includes a separate frame piece, measure the inside of the frame for both width and height. This will ensure your new door fits snugly within the frame.
  • For doors with trim or casing, measure from the inside edges of the trim on both sides and from the floor to the top of the trim. This will give you the most accurate measurements for your replacement door, taking into account the space needed for the trim.
  • If you notice that your floor is uneven, measure the height of your door frame at the highest point. When installing your new door, you may need to use a door sweep or make other adjustments to ensure a proper fit and seal.
A person preparing to measure a door frame for replacement.

Other Recommended Maintenance

While you’re focusing on your door replacement, it’s a good idea to take care of some other maintenance tasks. Inspect your door hinges and lubricate them with a silicone-based lubricant to prevent squeaking and sticking. This simple task can make a big difference in how smoothly your door operates.

Check your door’s lockset and make sure it’s functioning properly. If needed, adjust the strike plate or tighten any loose screws. A well-functioning lockset is essential for both security and convenience.

Finally, if you notice any drafts or feel cold air coming in around your door, it may be time to replace the weatherstripping. This simple upgrade can improve your home’s energy efficiency and keep you more comfortable year-round.

When to Call a Professional

Measuring for a door replacement is a relatively simple task! However, there are some cases where it’s best to call in a professional:

  • If you’re unsure about any part of the measuring or installation process, don’t hesitate to seek expert guidance. A professional can ensure that your new door is measured and installed correctly, saving you time and potential headaches down the road.
  • If you discover any structural issues with your door frame, such as rot or significant unevenness, it’s best to have a professional assess the situation. They can recommend the best course of action and make any necessary repairs before installing your new door.
  • If any part of the project is beyond your knowledge level, it’s best to leave the job to a pro. They’ll have the tools and expertise needed to make any necessary modifications and ensure a proper fit for your new door.


Figuring out how to measure a door for replacement may be a bit tricky at first, but with the right tools and guide, you can easily tackle this project. Just remember to measure the width, height, and thickness of your current door, and keep an eye out for any special situations like frames, trim, or uneven floors.

While you’re at it, don’t forget to take care of some other door maintenance tasks, like lubricating hinges, adjusting the lockset, and replacing weatherstripping. If you run into any issues, aren’t sure about something, or just want to schedule a thorough check of your home, call Alpha Building Inspections in NH, MA, and ME.