How to Measure

Measurement Diagrams

With so many different tap cartridges available, it is important that you take some measurements of the cartridge you are trying to replace.


This can be a bit daunting at first when you look at our measurement diagrams, but if you follow these steps, you should be able to find your replacement tap cartridge fairly easily.


Choose the diagram below that looks most like your existing cartridge, and then you can start to record measurements according to the letters on the appropriate diagram for use in the filters on the page contian.

1/4 Turn Ceramic Cartridges Without Threaded Collar

1/4 Turn Ceramic Cartridges With Threaded Collar

Compression / Washer Tap Valves With Threaded Collar

Compression / Washer Tap Valves Without Threaded Collar

Monobloc Cartridges

Measuring Tools

First of all you will need some measuring tools. If you want to measure very accurately, you can use a micrometer or calipers which you can buy relatively cheaply from Amazon or eBay, but if you can't get hold of one of those, then a ruler or tape measure will be a good starting point.


Tape Measure

We recommend you take as many measurements as possible in order to check that you are ordering the correct tap cartridges. They all look very similar, and you won't easily be able to tell which is the correct one just by looking at photographs of it.

Step 1 - BSP Thread Size

Establish whether your tap cartridge is for 1/2 inch or 3/4 inch. If you measure across the bottom of the cartridge and the measurement is around 24mm, then it is a 3/4 inch cartridge. If the measurement is more like 18mmm, then it is a 1/2 inch cartridge.


Once you know this, select the 1/2 inch or 3/4 inch filter on the tap-cartridges page.

This one is 24mm, so you can check the 3/4" box in the filters.

If it was 18mm, you would check the 1/2" box

Step 2 - Length excluding any screws

Next measure the length of your tap cartridge, exluding any screws that might be in the top and put that into the Measurement A filter.

Step 3 - Count the Splines

The splines are the ridges around the top of the tap cartridge. You will need to count them. The easiest way to do this is to use a black marker pen like a Sharpie to mark one of the splines, then count round until you reach the mark again. You can see this being done in our instruction video below.

An alternative method is to take a photo of the spline with your mobile phone. If you manage to focus on the spline, you should then be able to zoom in to it and that does make it easier to count the splines. This one has 20 splines:

For a demonstration of the above have a look at our video