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Behind Closed Doors: Unveiling the Drama of Australian Standard Door Thickness

Updated: May 31, 2023

I was asked if there was a standard door thickness? An interesting question as most door handle manufacturers generally supply fixing screws to suit 35mm to 45mm thick doors. Some extend to 50mm but generally they are less frequent.

In Australia, the standard door thickness is either 35mm or 40mm. Doors are an essential part of any building, providing privacy, security, and insulation. The thickness of a door refers to the measurement of the door panel itself, excluding any additional trim or molding.

A 35mm door is commonly used in residential buildings. It is a standard thickness that offers durability and functionality for everyday use. These doors are suitable for interior spaces such as bedrooms, bathrooms, and closets, where security is not a primary concern.

On the other hand, a 40mm door is often preferred for external entry points, such as front doors or back doors. The additional thickness adds an extra layer of security and insulation, helping to keep out noise, drafts, and potential intruders. These doors are designed to withstand more rigorous use and provide enhanced protection for the home or building.

It is worth noting that while 35mm and 40mm are the standard door thicknesses in Australia, variations can exist depending on specific requirements or preferences. With imported doors and Custom doors, thicknesses may vary for specialized applications or to meet specific building codes.

Overall, understanding the standard door thickness in Australia is important when selecting doors for your home or building project. It ensures that you choose the appropriate door thickness to meet your needs, whether it's for interior spaces or external entry points, taking into consideration factors such as security, insulation, and functionality.

Door thickness does vary. Depending on where you buy your doors, you will find the thickness of a door varies. Generally door thickness sizes run from 32mm to 50mm. Most Australian door manufacturers will supply the standard 35mm or 40mm. While imported doors can be 32mm/33mm and various other variations. When buying a door off the shelf always check the dimensions with a measuring tape.

Door Sizes

Common Door Size

  • In Australia the most common overall standard door size is 2040 x 820mm, and 2040 x 920mm, but there are other sizes that are popularly used. Door thickness can be 35mm for internal doors and 40mm for external. Variations do exist. One thing to note is that door frame size can vary which is why you may see a door being shaved.

Exterior Doors

  • In Australia, the sizes of exterior doors are somewhat standardized. This helps homeowners control their costs when building or renovating a property. Standard exterior frames are designed to hold doors 2040mm high and x820, x870, x920 or x1020 mm wide.

Door manufacturers in Australia do produce doors in common overall standard sizes (but door thickness can vary). This allows the customer to choose doors in a variety of colors and materials. When the door they like will fit the door frame the choice is easier.

Here are a few door sizes:

Height: 2040 by width

  • x520w;

  • x620w;

  • x720w;

  • x770w;

  • x820w;

  • x870w;

  • x920w.

Depending on the actual frame size, doors can be machined to custom size.

Standard Interior Frame Dimensions

Interior doors are smaller. The height for all interior doors must be minimum 2040mm. The standard width for interior doors is 620, 720, 770, 820, 870 or 920 mm. However door thickness can vary.

If you are renovating or building, know your door frame measurements. Interior doors are a little easier to install. You can modify the door frame according to the door size.

Panel Door Sizes

Interior panel doors have a standard size. Height is 2040 mm, x 620, x720, x770, x820, x870, or x920 mm.

Note: The thickness of the door can vary depending on manufacturing requirements.

Hollow Core Doors

Panel doors are usually made from wood and have vertical side styles and horizontal rails. Panel doors are known as a hollow core door and used for internal rooms. This reduces the material needed for building a door. Ultimately it cuts cost. They generally follow the standard 2040 x 820 x 35mm and can be shaved down to suit frame.

Flush Door Sizes

A flush door is 2040mm or 2340mm high and has a width of x420, x460, x520, x620, x720, x770, x820, x870, x920, or x1020 mm.

Note: The thickness can vary depending on who manufactured the doors. Flush doors are front and back surfaces that are largely flat. Made of wood sheets making them more affordable for interior doors. The surface of the door can be painted. Allowing color matching to walls.

Bifold Door Sizes

The standard height of a bifold door is generally 2040mm. The width depends on the number of panels being used. For example if 2 panels are used the width is 1800mm or 900mm each panel. For 3 panels x2700mm, for 4 panels x3600mm and so on.

Note: The thickness of the door does vary again, dependent on where you purchase them.

Bifold doors are folding doors. They open by folding back in panels. Primarily used in smaller size rooms to save space. This type of doors is expensive due to its complexity in construction and installation.

Glass Door Sizes

Glass doors are available in varying sizes. Again the height will be around 2040mm. Common widths are x520, x620, x720, x770, x820 or x870mm. Larger glass door sizes are a made to order option for specialty projects.

Note: The thickness of the glass is generally 13mm or 19mm but can vary.

Glass doors are popular in homes to bring the outdoors inside. Glass allows the natural light in side. Glass doors make the room feel and look bigger. Glass doors are usually with either a single sheet or with multiple glass panels. They can be framed or frameless. They can also be folding or swing type.

Fire Doors

Fire rated door leaves are manufactured with a pyropanel fire resistant core, these doors are fully tested and certified to AS1530.4 and AS1905.1, and are available in a variety of sizes and finishes in 30 minute, 1 hour, 2 hour and 4 hour fire resistance levels. 

  • Fire door sets are available in pairs or singles, and with panels over, including 38mm and 48mm (nom) thickness.

  • 30 minute and 1 hour door leaves are of ‘no metal’ construction type, allowing for easing hanging and lock preparation.

Door Thickness

When it comes to imported doors, the thickness can vary from the standard measurements in Australia. Imported doors are those that are manufactured outside of the country and brought in to meet specific demands or preferences. Since different countries may have their own standards and construction practices, the thickness of imported doors can differ from the standard door thickness in Australia.

Imported doors may come in various thicknesses depending on the origin and intended use. It is crucial to check the specifications provided by the manufacturer or supplier when considering imported doors. This will help ensure that the door's thickness aligns with the requirements and preferences of the specific project.

For example, doors imported from Asia or Europe might have different thickness options compared to the standard measurements in Australia. It is essential to communicate with the supplier or manufacturer to understand the available options and select a door thickness that suits the intended application and design.

When importing doors, it is advisable to work with knowledgeable professionals or consult with experts in the field who can provide guidance on the appropriate door thickness for your project. They can help navigate the variations in door thicknesses and ensure that the imported doors meet the necessary standards and requirements for functionality, security, and insulation.

Imported doors can deviate from the standard door thickness in Australia. It is crucial to communicate with suppliers, manufacturers, or industry professionals to understand the available options and choose a door thickness that aligns with the specific project's needs and requirements. The thickness of the doors can, and does vary.

Door thickness off the rack varies from supplier and manufacturer across the board. The overall standard size of a door you will find on most door supply racks. You will find doors from as thin as 25mm, and those growing to 32mm, 33mm, 35mm, 38mm, 40mm and 45mm variants are not uncommon.

Door Handle Height Matters

Regardless of the size of the door, the Australian Standard AS 1428.1 (Design for access and mobility, Part 1: General requirements for access) recommends that the height of the handle should fall within 900mm and 1100mm above the floor.

This is around waist height for the average adult. Generally speaking, only much older doors or those installed for a special purpose will deviate from this recommendation.

There is no standard door thickness...

You will find some door suppliers stating that the standard door thickness is 35 or 40mm because that is what the manufacture. While others will tell you its 33mm or 38mm depending on what they have on their racks.

The bottom line is door thickness does vary. Today when there are so many imports and suppliers, the 'standard' off the rack door thickness has varied.

Fixing Screws for Door Handles

The issue for door handle manufacturers is how to cater for varying door thickness. There are numerous door thickness' and only so many fixing bolts they can supply to go through the thickness of a door. Most Australian door handles will have screw fixings to cater for a 35mm to 45mm thick door.

Some manufactures in their wisdom supply either 45mm (some 50mm) tie through bolts so that they can be cut down to size.

Because door thickness does vary it becomes difficult to cater for all possibilities. And for the sake of a hacksaw blade, you can cut back when necessary. Lockwood state door thickness can be anywhere from 32mm to 50mm as standard for there door levers.

Entrance Handles

Most entrance handles or pull handles come with 110mm bolts when used on wooden doors. The bolt head depth is around 25mm and the thread into the receiving leg is around 25mm leaving 60mm for door thickness.

If you door is more than 60mm thick you will need longer bolts. In these situations what we try to do is supply suitable ferrules and a bolt long enough for the job. Not always easy or available. We may have to create something to make it work.

Does door thickness matter...

So, does it matter how thick your door is? When the door is closed how thick does it look? A closed door looks... flat.

The only time you know the thickness of a door is when it is open. An open door is something you walk through and close behind you. When its closed it looks... flat.

The benefit of a thick door

If you owned a castle and the front gates were extra thick it would deter would be invaders. However having a thick door on your entry to your house is perhaps for show only. If the walls do not correspond with the door thickness not much is achieved. That's not to say you shouldn't have thick doors if that is what you want, I just don't see the benefit when the door is closed.

Ideally thick walls and matching doors would keep outside noise to a minimum. But there are other ways to achieve the same result by using door seals for example.

The other downside to having a thick door is that you still have to open it!

Opening a thick door

Opening a thick door can be difficult if the door is not hung effectively. If hinges are the hanging point the weight of the door will require strength to close and open it. Ideally a floor pivot system would do the job nicely allowing easy open and close access. We have a solution for that too. View our door closers here


Doors do come in different thickness. Whilst some manufacturers provide their standard door thickness, others offer alternatives. Some are even based on cost.

You will find some door manufacturers will use their standard size in the industry. Whilst others will use different sizes in their manufacturing.

A lot will depend on where you purchase your doors. Are they made in Australia or are they imported. Most imported doors tend to vary thickness probably due to manufacturing processes.

As long as the door is equal too, or greater than the frame size, it can be made to fit. And that is more important than having a door that is too small for the frame.

Whatever the scenario, at Architectural Design Hardware we will try our best to accommodate your needs and requirements when you purchase door handles and entrance handles from us.

If you have questions, we will try to assist.

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