Ever Wondered What All The Markings On A Measuring Tape Are For?

We’re pretty sure most people know how to use a measuring tape, but what you probably don’t know is what all of the different markings mean. Have you noticed the roman numerals and black diamonds?

Metric & Imperial Markings


If you live outside of the UK, chances are your measuring tape will have either metric or imperial measurement grades and units on it. In the UK however it is quite common to get measuring tapes with both as the European Union has enforced use of the metric system however many tradesman still prefer to use imperial units.

How Accurate Is Your Measuring Tape?


Pull out your tape and in the first few centimeters or inches there should be a roman numeral printed inside a rectangle or circle, this numeral refers to the accuracy of the measuring tape.

There are generally four grades of accuracy with Class 1 or I being the most accurate and and Class 4 or IV being the least accurate. If you’ve bought a cheap or unclassified tape, it won’t have any Class markings on it which simply means that is has not been tested and therefore doesn’t guarantee any level of accuracy.

The Length


The total length of your tape measure is generally printed in red somewhere right near the tip of the tape in red. If you have a tape measure with both imperial and metric units, the length of both with be shown next to their respective scales.

Now Here Are The Less Known Tape Measure Markings

Black Diamonds


You may have noticed that there are little black diamonds every so often down the length of your tape measure. They are used by tradesman as stud and joist marks, stud marks typically occur at 16″ intervals and joist marks at 19.2″ intervals. These may seem like strange denominations but they are derived from the fact that most American building materials come in 8ft lengths, 8ft divided 5 times gives you the perfect width for joists which happens to be 19.2″ as indicated on the tape.

Year Of Manufacture


The last two digits of the year of manufacture is often written alongside an M in a red or black rectangle. The year of manufacture is printed onto most modern tapes as a means to identify that it was manufactured to conform to a certain set of regulations applicable at that time.

CE Marking


If your tape was bought in Europe or manufactured with resale within the European Union in mind then it should have a CE printed on it, this means that it conforms to all of the European Union regulations applicable to it during the time of manufacture. It doesn’t mean it was manufactured in the EU but it does suggest that it was intended for resale there.

Testing Body


Somewhere near the year of manufacture, there may be another four digit number within a rectangle, this number relates to the agency responsible for the issuing of the certification. The codes can generally be looked up online and correspond to a registered institution or laboratory.

Images and Content Credit – The Tape Store

Michael Klements
Michael Klements
Hi, my name is Michael and I started this blog in 2016 to share my DIY journey with you. I love tinkering with electronics, making, fixing, and building - I'm always looking for new projects and exciting DIY ideas. If you do too, grab a cup of coffee and settle in, I'm happy to have you here.


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