How much space should be at the top and bottom of a door?

Author: Gene Collins DDS  |  Last update: Monday, June 8, 2026

A well fitted door should have a 2mm gap on either side and at the top. The gap at the bottom will depend on the thickness of your flooring/carpet.

How much space is above and below the door?

Having a gap allows for the smooth opening and closing of the door, preventing scraping and wear of the door itself or the floor underneath. There are safety concerns to consider as well. In general, the gap beneath an interior door will be between three-quarters of an inch and half an inch.

How much clearance do you need for the bottom of a door?

Internal Door Undercuts

As a guide the average undercut of your door should be between 8mm and 10mm, that's around ⅝ inch to ¾ inch from the bottom of the frame.

How much space to leave at the top of the door?

Top (Header) Margin: Space at the top of the door panel. A typical top margin or header margin is 1/8".

What should the gap be around a door?

There should be a 2mm or 3mm gap between the door and the frame on both sides and the top. If you do need to cut the door down to size, keep in mind that you need to cut all four sides of the door equally whenever possible to retain an accurate shape or pattern if the door is panelled.

How do I fix large gap at bottom of my door? Simple Fix!

How much gap should be at the top and bottom of a door?

TRIMMING TO SIZE

A well fitted door should have a 2mm gap on either side and at the top. The gap at the bottom will depend on the thickness of your flooring/carpet. Plane the door as required, using an electric plane will help you get an even finish, and sand for a smooth finish.

What should the clearance be around a door?

Ideally, there should be a gap of about 1/2 inch between the bottom of the door and the floor to allow for expansion and contraction due to temperature changes. Additionally, side clearances should be approximately 1/8 inch on both sides to ensure smooth operation.

What is the ideal door gap?

A gap of around 1/8th of an inch is recommended for standard doors to keep the elements out, protect the paint on the trim, and ensure that the door closes and opens smoothly. The right amount of space is equal to the thickness of your door with a little extra room for clearance while opening or closing.

How much of a gap between door and floor?

In this article, we'll cover everything from selecting the right interior wood door size to ensuring proper clearance and alignment. One critical aspect to emphasize is the gap between the door and the floor, which should be between a half-inch and three-quarters of an inch for optimal functionality.

How much space is between the top of a door and the ceiling?

What is the code for the gap under a door?

NFPA 80 currently allows a maximum bottom gap of 3/4 in.

What is the standard clearance for a doorway?

Door openings shall have a minimum clear opening width of 32 inches; however, if the doorway is more than 24 inches deep, then a minimum clearance of 36 inches is required. The clear opening is measured from the face of the door to the stop of the frame while the door is opened to 90 degrees.

How much smaller does a door need to be than the opening?

Measure this in three places—the top, middle, and bottom of the opening, and then use the smallest of these three measurements. Then, subtract 2″ from this width. This equals the needed door width. Example: Rough opening width = 38″.

How much of the bottom of a door is solid?

Generally an inch at most, but half an inch to be safe. The solid filler at the bottom isn't much more than an inch 'tall' inside there. If you need to cut more than that, you will then have to replace that filler piece with some wood material glued in place between the luan sides.

Is there a top and bottom to a door?

Top Rail: Located at the top of the door panel. Bottom Rail: Found at the bottom of the panel.

How to measure a door gap?

The measurement is taken between the bottom outermost edge of the doors and the top of the floor surface beneath the doors.

What is the acceptable door gap?

the gap between the underside of the door and unfinished floor should be between 10mm and 22mm, with the ventilation requirements for the building taken into account when determining the gap beneath internal doors.

How do I reduce the gap between my floor and door?

An effective solution for you to close the gap between your door and floor is by installing door thresholds. These are used mainly for the purpose of closing the gaps between the floor and the bottom surface of the door. You may require trimming the threshold as well.

Should wood doors match floor?

It is definitely a matter of personal taste, but as the one holding the big picture vision, you will need to keep a few things in mind. Too many different shades of natural wood in the home might clash. An oak floor might not look great with a door in the shade of maple.

How high should a door be above the floor?

Ideally, the threshold should be higher than the interior finished flooring by 1/2″ to 3/4″. This is high enough for the door to clear the flooring when it is opened, but low enough not to be a stumbling block to those who pass through the door.

How much gap under door for return air?

In most applications, the door undercut would need to be 1.5 inches or greater to allow enough air to pass. There are some through-the-door alternatives that can be effective.

What is the gap under a door code?

NFPA 80 (the code standard for fire doors) states that fire doors must be inspected on an annual basis. Maximum allowable perimeter gap is 1/8" for wood doors, 1/8" +/- 1/16" for metal doors. Maximum allowable door bottom gap is 3/4".

What is the standard undercut of a door?

Undercut is a term used to describe the dimen- sion from the bottom of the door to the bottom of the frame. Doors are undercut to provide clearance above the finish floor material. Typically they are undercut ⅝ inches to ¾ inches from the bottom of the frame.