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How to Measure for a UPVC Door Lock

This article is a collaborative effort, crafted and edited by a team of dedicated professionals.

Contributors: Muhammad Baballe Ahmad, Mehmet Cavas, Sudhir Chitnis, and Zhen-ya Liu.

✓ Verified & Tested Information

This blog post will teach you how to measure for a UPVC door lock . By following the instructions in this post, you will be able to get the measurements you need in order to purchase the correct size lock for your door.

Tools Needed

Measuring for a UPVC door lock requires the correct tools and measurements. You will need to have a tape measure, pencil, and paper to take measurements and make any necessary notes. Additionally, you may need a drill and a drill bit to make any necessary holes for the lock to fit. Before we get into the measuring process, let’s make sure we have the essential tools necessary.

Tape measure

Using a tape measure will allow you to accurately measure the door so that you can make sure that the new UPVC door lock will fit correctly. It is important to take multiple measurements when measuring for a new lock, in order to best determine which type of lock is right for you.

When measuring your door, it is important to account for each side and ensure that there are no obstructions like wooden trim or insulation that could interfere with the new lock’s installation. If necessary, remove any exterior items before taking your measurements as this helps to get an accurate representation of your door size.

Measure the width of your door by starting at the left side and running the tape measure along its length until you reach the far side. Record this measurement and move on to measuring the height of your door by positioned at its top left corner, then run the tape measure up until you reach its opposite corner. Record this measurement too, then add them together and finally double-check all measurements before proceeding with installation.
Make sure that both entries and exits are measured so that correct locks can be purchased based upon these measurements.


A pencil is an essential tool for marking out the position of a UPVC door lock. It is important to ensure that the drill hole for the cylinders is accurately placed or it may not fit correctly. You should use a pencil or felt-tip pen to mark out exactly where you need to drill. Depending on the type of lock you are using, it may be necessary to measure and mark out more than one hole. It can be helpful to draw around the cylinder escutcheon, latch striker, and faceplate in order to make sure they are accurately located when they are eventually fitted. Marking up your measurements with a pencil will help you avoid any mistakes when fitting your locks.


A screwdriver is a critical tool you will need to measure for a UPVC door lock. Depending on the size of the screweyes and screws used to attach the lock, you may need either a Phillips-head or flathead screwdriver. It is also beneficial to have both sizes available in order to ensure accuracy – especially when measuring for handles with different backplate profiles or levers with different spindle lengths.

The majority of UPVC doors have three mounting points – one at the top, one at the bottom and possibly one in between. To measure accurately, you need to unscrew each mounting point and take note of the length and profile of each screweye or screw. When making notes, take into account whether these points are spaced 12 mm apart (for metric locks) or 16 mm (for imperial), as this affects how the handle looks on your door. To complete your measurements, it’s important to reinstall each mounting point before beginning installation , as this can affect how securely your new UPVC door lock holds against the frame .

Measuring the Lock

When installing a new UPVC door lock, the first step is to measure the lock correctly. This is essential for the door lock to fit the door frame properly. Measuring for a UPVC door lock can seem overwhelming, but with a few simple guidelines it can be done quickly and easily. Let’s explore the steps to measure for a UPVC door lock.

Measure the backset

When measuring a UPVC door lock, you’ll need to measure the backset, which is the distance from the edge of the door to the centre of the keyhole or keyhole cylinder. Once you’ve located the centre of the keyhole, use your ruler or tape measure to determine this distance – typically either 35mm or 45mm. Measure from both sides and sides of your door to make sure that you record an accurate measurement for backset. Ensure that you take into consideration any architraves that might be positioned around your doorknob. This will help give you a more precise backset measurement, ensuring that you purchase a lock that fits perfectly.

Measure the centre of the spindle to the centre of the keyhole

To begin to measure for a UPVC door lock, start by measuring the centre of the spindle to the centre of the keyhole. This will give you the correct backset measurement for your door. The definitive characterisation helps ensure that all components fit together correctly when final installation is taking place. Usually, this measurement will be one of three sizes: 55mm, as this is the most commonly used, or 45mm and 75mm which are both less common sizes. Measure carefully as, if you get this wrong, your door may not accept the lock components correctly and pose a security risk. Once you have identified that dimension properly it’s possible to move on with selecting the right mechanism for your door securement needs.

Measure the centre of the keyhole to the edge of the door

When measuring the door handle and lock size, start by measuring the distance from the centre of the keyhole to the edge of the door. To do this, first measure in a straight line (not diagonally) from one edge of the door to the other, being sure to use either a ruler or tape measure that is designed for measuring doors. When you have your measurement, write it down and refer to it when selecting your new locks.

Next, measure from side to side across the lock face. This will give you its width. You may need to take into account any recesses in which a standard size lock may not fit properly. Next find out how thick your lock should be as this can affect how deep its holes are drilled into it when fitting it into place on your upvc door. The thickness is measured along the dividing line between where two catches meet on each side of an upright cylinder type lock handle or thumb turn.

Finally, you should measure how long your cylinders are so that you can ensure that they will fit into both sides of the UPVC door securely without sticking out unnaturally far from either edge . This measurement is taken from one end of each cylinder barrel – usually up near where their keys fit – to its other end when they are put together with their opposition opened slightly revealing a tiny gap between them at either side in order for both lockshields to connect perfectly within your door fame and frame itself when later installed correctly.

Installing the Lock

Installing a new UPVC door lock can seem like a difficult task, but with the right tools and a bit of knowledge it’s not as hard as it might seem. The first step to installing your UPVC door lock is measuring for the lock. Measuring for the lock is an important part of the process and it’s important to get it right. In this section we will go over the basics of measuring for a UPVC door lock.

Mark the position of the lock

It’s important to measure accurately when installing the lock on your UPVC door. To begin, you will need to mark the position of the lock on the UPVC door. Make sure that you have considered where it needs to be located in terms of height and width.

Take a level and mark the center line at both 90cm from the floor (for most standard sized doors) and also at 710mm from the handle side, if this is applicable. To mark this position, make a drill mark in pencil at each end of the line on both sides of the glass panel or wooden frame – whichever is applicable. Then use a metal straightedge to draw visible lines between these two points, creating your center line for lock installation.

Using a square-bladed screwdriver, untighten all screws on the template while leaving them in place so that they can be reattached easily once you have completed your measurements correctly. As a guide if you are replacing an existing lock then make sure that you use similar sizes for both backset (distance from handle side) and centre measurement as these relate to overall size of case etc.

Drill the holes for the screws

Once you have determined the placement of the lock and latch mechanism onto your door, you will need to drill two holes for the mounting screws. You will want to be sure to use a drill bit that is properly sized to fit the screws as well as a level or other straight edge tool to ensure you are drilling in a straight line. You will want the holes at 5mm diameter and 20mm deep for most modern UPVC door locks. Be sure not to force the bit into the door, as this could cause damage or misalignment. After drilling, insert the two screw studs included with your lock set then tighten them securely in place.

Install the lock and screws

Begin by installing the spindle and lock case in the desired position on the door. Ensure that you have fitted the parts firmly and squarely – this will drastically reduce any future maintenance issues.

Once the lock is in place, secure it using screws. Use your Phillips screwdriver to secure each end of the spindle into both halves of the lock case. Then use a masonry bit or pilot hole to make holes in the door prior to fitting screws in its correct position securely. Use scratch resistant screws with a flat head on handles to avoid possible scratches from a cross head screw.

If you are having difficulty keeping doors shut then a spring latch is recommended to be installed after the lock has been positioned correctly. Before installation, hold up a latch and check for dimensions as well as type – conventional or security for instance – as this will determine how it fits with your lock system. Sliding bolt latches may also be used depending on how much additional security is required for your door frame as these are locked by two separate bolts that are secured into place simultaneously when closed.

Testing the Lock

Once your new UPVC door lock is in place, you’ll want to make sure it works properly before you put it to use. Testing the lock before you install it is important to ensure it will make a secure fit. There are a few different tests you can use to measure for a UPVC door lock, including measuring the depth of the lock, the size of the cylinder, and the overall length of the lock. In this section, we’ll explain each of these tests in more detail.

Test the lock for proper operation

To effectively measure for a UPVC door lock, you must first test the existing lock to make sure it is in good working order. The best way to test the lock is to open and close the door several times – check that both latches engage securely and move freely, with no sticking. It is important that both locks are operating correctly in order to maintain the security of your property.

Next, inspect the edges of the door carefully to make sure there is nothing preventing it from latching properly. This could be anything from an uneven flooring surface or an obstruction within the frame. Then, if necessary, adjust the latch mechanism using a screwdriver or hex key to ensure it can latch properly.

Finally, measure each side of your UPVC door separately – measure between where your existing locks lock and on the faceplate side (on both sides). Record these measurements and use them when selecting a replacement lock for your UPVC door. You will also want to consult a locksmith adviser if you have any questions or concerns about fitting and selecting an appropriate replacement for your needs.

Check for any binding or sticking

When installing a UPVC door lock, it’s important to ensure proper fit and function prior to final installation. One of the most effective ways to do this is to test the lock for any binding or sticking before committing. This can be done by closing and opening the door multiple times, paying careful attention to anything that may feel loose or tight. Be sure to check the latch travel too – it should move smoothly back and forth without interruption. If any sticking occurs, there may need to be adjustments made with adjusting screws located at each corner of the latch assembly. These screw movements need only a slight adjustment in order to secure good action on the latch plate. Correcting this is essential in order for proper function of your UPVC door lock system.

Check for proper alignment

Proper alignment is crucial when it comes to UPVC door locks. If the lock isn’t aligned correctly, it won’t engage properly and you won’t be able to open the door as easily. To ensure that your lock is installed correctly, there are a couple of tests you can use.

First, you need to check for proper alignment with a measuring tape. Place the measuring tape across the slot at the top of the door and measure from each end of the slot to where it meets with its respective body part on either side of the door. Make sure that both distances are equal and within 2mm-3mm of each other– if they aren’t, it may be necessary to adjust the frame or locking mechanism accordingly.

Next, you’ll need to perform a jiggly test on your lock by opening and closing your door several times (more than two hundred should do). Be sure to hold onto your handle as you do this; if you feel any vibrations or movement in either direction more than 1/4th inch, then it means that something may be out of balance and needs adjusting. Doing this test will ensure that there is no obstruction in either direction when unlocking or locking your door from both sides.

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