Rough Opening of 36-Inch Door
Exteriors Interior

What is Rough Opening of 36-Inch Door?

Are you planning to replace a door and are confused about measuring the rough opening? Don’t worry; this guide will simplify the process for you. We will help you understand the concept of rough opening, show you how to measure it, and determine the right size for doors ranging from 28 inches to 36 inches in width.

What is a Door Rough Opening?

The rough opening is the area in the wall where the door will be installed. It includes the horizontal distance from the floor to the header and the vertical distance from the floor to the top of the frame studs. The standard unit of measure for these distances is inches.

When replacing a door, it is crucial to measure the old one and buy a prehung door with matching dimensions. Prehung doors come with a frame, so only minor adjustments are needed during installation.

Door Size Rough Opening
24″ X 80″ 26″ X 82 1/2″
28″ X 80″ 30″ X 82 1/2″
30″ X 80″ 32″ X 82 1/2″
32″ X 80″ 34″ X 82 1/2″
34″ X 80″ 36″ X 82 1/2″
36″ X 80″ 38″ X 82 1/2″

How to Determine the Door’s Swing Direction?

Stand in the doorway with your back to the hinge side to determine the door’s swing direction. If the door opens to your left, it is a left-hand door. If it opens to your right, allowing your right arm to swing through it, it is a right-hand door.

Measuring the Door’s Rough Opening

To calculate the rough opening of your door, add a few extra inches to your door’s width and height measurements to ensure a good fit.

Width Formula:

Inches of your door + 2 inches (wide) = Rough door opening

Height Formula:

Inches of your door + 2-1/2 inches (tall) = Rough door opening

These extra inches provide the room required to fit the door frame and guarantee proper installation for both single and double door units. Remember that these dimensions are typical for interior prehung doors.

For instance, if your door is 30 inches wide and 80 inches tall:

  • The rough opening width will be 30 inches + 2 inches = 32 inches
  • The rough opening height will be 80 inches + 2-1/2 inches = 82.5 inches

Therefore, the rough opening measurements for an interior door would typically be 32 inches wide by 82.5 inches tall.

Rough Opening Sizes for Different Door Sizes

36-inch Interior Door

For a single door that is 36 inches wide and 80 inches tall, the suggested rough opening dimensions would be 38 inches wide and 82.5 inches high.

36-inch Exterior Door

For a 36 inches by 80 inches pre-hung exterior door, the rough opening should be 38.5 inches wide and 82.25 inches high. Generally, you need to add 2.5 inches to the width and 2.25 inches to the height of exterior single doors for rough opening.

34-inch Door

For a 34 inches wide and 80 inches tall door, the rough opening should be 36 inches wide and 82.5 inches tall.

32-inch Door

For a 32 inches wide and 80 inches tall door, the rough opening should be 34 inches wide and 82.5 inches tall.

30-inch Door

For a 30 inches wide and 80 inches tall door, the rough opening should be 32 inches wide and 82.5 inches tall.

28-inch Door

For a 28 inches wide and 80 inches tall door, the rough opening should be 30 inches wide and 82.5 inches tall.

Importance of the Rough Opening

The rough opening is crucial for a successful door installation as it accommodates the door jambs and allows the door to swing freely. Wider door openings are necessary for easy passage, especially when considering wheelchair accessibility and mobility aid clearance.

Creating a buffer zone by leaving enough room for door installation allows for adjustments to ensure the door is straight, flush, level, and square within the frame. This buffer zone also accounts for the natural expansion and contraction of the wall due to variations in humidity and temperature, ensuring the door’s long-term stability and functionality.

Tips for a Successful Door Installation

Check for Square: Before installing the door, use a carpenter’s square to check that the corners of the rough opening are square. This will help ensure that the door will fit and operate correctly.

Level the Sill: Make sure that the sill (the bottom of the rough opening) is level. Use a long level and, if necessary, shim the sill until it is perfectly level.

Use Quality Materials: Don’t skimp on the quality of the door, frame, or hardware. High-quality materials will ensure that the door operates smoothly and lasts a long time.

Seal the Opening: Make sure to properly seal the rough opening to prevent water and air infiltration. Use a good quality caulk and weatherstripping.

Secure the Door Properly: Use long screws to secure the door frame to the rough opening. Make sure to screw through the jamb, shims, and into the framing of the wall.

Adjust the Door: After the door is installed, check its operation. Make sure it swings freely, latches securely, and that the weatherstripping seals properly. Adjust the door if necessary.

Door Installation Tools and Materials

Here is a list of tools and materials that you might need for a door installation project:

Tape Measure: To measure the dimensions of the door and the rough opening.

Carpenter’s Square: To check that the corners of the rough opening are square.

Level: To ensure the sill and header of the rough opening are level.

Shims: To adjust the door frame so it is plumb and level in the rough opening.

Screws: To secure the door frame to the rough opening.

Drill: To make pilot holes for the screws.

Caulk: To seal around the door frame and prevent air and water infiltration.

Weatherstripping: To seal around the door and prevent drafts.

Door: The door you will be installing.

Door Frame: The frame that the door will be installed in.

Types of Doors

Panel Doors: The most common type of interior door, featuring a frame and one or more panels.

Flush Doors: Simple, flat doors with a plain surface. These doors are typically more affordable and may be either solid or hollow.

Sliding Doors: These doors slide horizontally on tracks and are commonly used for patios or closets.

French Doors: These are hinged double doors with glass panes extending most of their length.

Pocket Doors: These doors slide horizontally but disappear into the wall when fully open.

Bi-Fold Doors: These are folding doors that are commonly used for closets, pantries, and laundry rooms.

Dutch Doors: These are divided in half horizontally and allow the top and bottom to open and close separately.

Barn Doors: These are large, heavy doors that slide horizontally on tracks. They are commonly used for barns and sheds but have also become popular as interior doors.

Door Maintenance

Proper maintenance is crucial for ensuring the longevity and functionality of your doors. Here are some maintenance tips:

  1. Regular Inspection: Regularly inspect the door for any signs of wear and tear. Check for loose screws, worn weatherstripping, and any other damage.
  2. Lubricate the Hinges: Regularly lubricate the door hinges to ensure smooth operation.
  3. Clean the Door: Regularly clean the door and its frame. For wooden doors, use a wood cleaner and polish. For glass doors, use a glass cleaner.
  4. Seal the Door: Regularly check the caulk and weatherstripping around the door. Replace if necessary to ensure a good seal.
  5. Paint or Stain: Regularly paint or stain wooden doors to protect them from the elements.

By following these tips and maintaining your doors properly, you can ensure they will last a long time and continue to operate smoothly.


What is the Most Common Door Opening Size?

The most typical door opening dimensions in residential construction are 36 inches wide by 80 inches tall, commonly referred to as a standard or “prehung” door size.

What to Do if the Rough Opening for the Door is Too Big?

You can either install a larger door or use door trim or casing to cover the extra space around the door. If you need a different solution, consult a qualified builder or contractor who can resize the opening by creating a new frame or adding more framing material.

How Much Room Do You Need for a Rough Opening?

Aim for a rough opening that is 2 inches wider and 2.5 inches taller than the door itself.

What is the Rough Opening for a 60-inch Double Door?

For a 60-inch wide and 80-inch tall double door, the rough opening should be 122 inches wide and 82.5 inches tall.

What is the Gap Between the Door and the Frame?

A 1/8-inch gap should exist between the door’s head rail, hinge stile, and lock stile. Additionally, the gaps between the door and its frame should be less than 1/16 inch or roughly 2mm.


Determining the rough opening size for a 36-inch door is simple using the provided formulas. By accurately measuring the rough opening, you can ensure a seamless installation process. Remember, a successful door installation requires creating an appropriate rough opening size. Armed with this knowledge, you can confidently move forward with your door installation project.

Nyla Rose

Say hello to Nyla Rose, a special person who helps people make their homes pretty and comfortable. Mary went to the University of Creativity to learn all about making spaces beautiful.

For more than 10 years, she’s been sharing her smart and fun ideas about home decorating with people all around the world. Mary loves to talk about cool DIY projects, how to decorate on a budget, and choosing the perfect items for your home. Her friendly tips and stories are loved by many because she makes home decorating easy and joyful!

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