Interior Door Sizes: Standard Measurements and How to Measure Correctly
Interior Door Sizes: Everything You Need to Know
Getting the right door size is essential whether you are replacing an existing door or framing a new opening. Incorrect measurements lead to gaps, sticking, improper operation, and the frustration and cost of returns. This guide covers standard interior door sizes and the correct way to measure for a new door.
Standard Interior Door Dimensions
Interior doors in most homes follow standardized dimensions:
- Height: The standard interior door height is 80 inches (6 feet 8 inches). Some newer homes and custom builds use 84-inch (7 feet) or even 96-inch (8 feet) doors for a more dramatic, modern look.
- Width: Standard widths include 24 inches (closets and small spaces), 28 inches (minimum code for bedrooms in many areas), 30 inches (common for bedrooms and bathrooms), 32 inches (comfortable passage width), and 36 inches (recommended for main rooms and accessibility compliance).
- Thickness: The standard interior door thickness is 1-3/8 inches. Exterior doors and some premium interior doors use 1-3/4 inch thickness for added weight and sound insulation.
How to Measure for a Replacement Door
When replacing an existing interior door, measure the door slab itself rather than the opening. Measure the width at the top, middle, and bottom of the door. Measure the height on the left side, center, and right side. Measure the thickness. Use the largest measurements and round up to the nearest standard size.
If the existing door is unavailable to measure (it has already been removed), measure the inside dimensions of the door frame. The rough opening width minus 2 inches (for the frame on each side) gives you the approximate slab width. The height of the opening minus the threshold height gives you the approximate slab height.
Measuring for a New Door Opening
When framing a new doorway, the rough opening should be 2 inches wider and 2-1/2 inches taller than the door slab size you plan to install. This extra space accommodates the door jamb (3/4 inch on each side for width) and allows for shimming and leveling during installation.
Accessibility Considerations
If you need to meet ADA (Americans with Disabilities Act) guidelines or simply want wider clearance for easier movement, the minimum clear opening width should be 32 inches, with 36 inches recommended. This means using a 36-inch wide door slab. The clear opening is measured with the door open 90 degrees, so account for the door stop and hinge-side reduction when calculating actual clear width.
Double Door and French Door Sizes
Double doors or French doors consist of two door panels that meet in the center. Standard double door openings range from 48 inches (two 24-inch doors) to 72 inches (two 36-inch doors). The most common configuration uses two 30-inch panels for a 60-inch opening. When specifying double doors, note whether both panels are active (operable) or if one is a fixed panel with flush bolts.
Special Size Doors
Closet bypass (sliding) doors come in paired sets sized for the opening width. Common widths are 48, 60, and 72 inches for the pair. Barn doors should be wider than the opening they cover, with 4-6 inches of overlap on each side recommended. Pocket doors are the same standard sizes as hinged doors but require a pocket frame that doubles the wall width requirement.
Common Measurement Mistakes to Avoid
Do not measure the trim or casing and assume that is the door size. Always measure the actual slab or frame opening. Do not forget to account for flooring thickness if new floors will be installed after the door. Remember that older homes may have non-standard door sizes that require custom ordering. When in doubt, take your measurements to a door supplier who can help you determine the correct size and suggest solutions for non-standard openings.