The Ultimate 2024 Guide to Choosing Standard Interior Door Handles UK


Burlington Piccadilly in Antique Brass

Knowing standard door handle sizes makes it much easier to choose the correct-sized handles for your doors. With this knowledge, you can replace your door handles with new ones, making home improvements and renovations a breeze. 

Understanding Door Handle Dimensions

Understanding door handle dimensions is essential for ensuring you fit the correct handles to your doors. However, getting to grips with the terminology can be confusing, so we explain it here. 

“Backset” refers to the distance between the centre of the lock follower ( 8mm square hole) and the edge of the door. The backset is essential because it determines whether the lock you buy will fit your door, if you're replacing existing locks. If the distance is wrong, they will not fit.

The “fixing size” is the distance between the mounting holes on the door handle. Fixing size matters because it determines whether the handle or knob will align with any pre-drilled holes in your door and lockcase. If the holes are the wrong distance apart, you may not be able to fit the handle, or you may need to drill new holes. 

The “PZ” measurement is the distance between the centre of the doorknob or lever handle to the centre of the keyhole. The longer this distance, the more elaborate the handle’s internal mechanisms need to be. 

The PZ measurement isn’t as critical as the other measurements listed here. However, it can affect your door’s aesthetics. A longer distance may appear asymmetric. 

Standard Sizes for Interior Door Handles

Most common backsets for tubular latches are 44mm, 57mm and 82mm. For large case locks also referred to as UK lock case 64mm or 2 ½ inch locks or 57mm for 76mm or 3-inch locks. However, various sizes are available. The same is true for fixing sizes. Here’s a table listing the standard sizes in the UK:

Table of UK standard interior door handle backset and fixing sizes


Fixing size



44mm (1¾ inches)






57mm (2¼  inches)














82mm (3¼ inches)





107mm (4¼ inches)






130mm (5⅛ inches)


How to Measure for Door Handles

Fitting door handles successfully requires you to measure them accurately. Make sure you have a tape measure and pencil handy. Here’s a step-by-step guide on how to measure fixing hole spacing, backset and door thickness. 

Door Thickness

  1. Choose your measuring points. These should represent the thickness of the door at the point where you will install the lock.
  2. Take the measurement holding the tape flat on the edge (the narrow section of the door)
  3. Write down the measurement on paper so you don’t forget it. 

Hole Spacing

  1. Find any pre-drilled holes in the door’s exterior for the handle. 
  2. Position the tape measure between them, taking your measurement from the centre of the hole. 
  3. Write down the distance on paper, repeating the measurement to double-check accuracy. 


  1. Use a rule or straight-edged tape measure. 
  2. Place the measuring device against the door so that it is flush with it. 
  3. Estimate the centre point of the borehole and measure the distance to the door’s edge. 
  4. Write down the measurement on paper. Ensure you repeat the process a couple more times to ensure accuracy. 

When measuring any of these distances, double-check them. Ensure you use a rigid measuring device (not a soft tape) to get more accurate results. 

Sometimes you may need to measure the PZ distance when the door knob and locking mechanism are separate (on most exterior doors, they will be part of the same unit). To measure this distance, always measure from the centre of the handle to the centre of the locking mechanism. You want the distance to be comfortable and meet your aesthetic requirements. 

Selecting the Right Size Handle for Your Door

When selecting the right size handle for your door, you will need to consider the fitting size, backset and door width. Making mistakes could mean having to return your handle to the vendor. Interior door handle with lock

Fitting Sizes

Interior door handles usually have fitting sizes between 3 and 5 inches. Smaller sizes often mean more affordable fittings, which is helpful if you have a lot of interior doors. 

By contrast, most exterior door handles have fitting sizes between 4 and 5 inches. Manufacturers equip them with a longer distance between the holes to accommodate fittings with superior visibility and firmer grip. 


People also use longer backsets for exterior doors for more security. Making the backset longer makes it harder to interfere with the latch. It also gives the locking mechanism a smoother feel and better balance. 

Longer backsets are also suitable for double doors. Having a longer latch improves alignment and the feel of the lock when the doors close. Furthermore, you may see longer backsets on higher security doors. Making this distance longer lets manufacturers accommodate improved locking mechanisms to deter break-ins. 

Door Width

Finally, you will need to consider the door width: the distance between the doors’ interior and exterior-facing surfaces. That’s because the door handle’s spindle length takes door width into account. You will need longer spindles for wider doors. 

Additional Tips And Considerations

When choosing a door handle, you should consider: 

  1. The door’s backset distance. Manufacturers will list suitable backsets in the handle’s specifications, letting you know which will fit. 
  2. The style of the door. Antique handles pair well with vintage doors, while minimal handles work better with contemporary designs. 
  3. The finish of the door handle. It should match your door’s finish. Various options are available, including brass, anodised, and porcelain. 


This post helped you choose the correct-sized handle for your door. We learned that you need a handle that matches your door’s fitting size and backset. The handle should also have a suitable PZ distance and be suitable for your door’s width. 

Now you have this information, you are ready to use this guide for your home improvement projects and pick the proper handles for you. Browse our collection for more options. 

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