In Nostalgia

Ever Wondered Why Measuring Tapes Have A Black Diamond On Them? This Is Why!

By Ciara1 on February 24, 2017

Most of us have used a measuring tape at least once in our lives, but not all of us actually know what the numerical markings mean. I’m about to give you the full low-down on how to use your measuring tape.

So, we all know that the larger numbers at the top represent inches and the smaller numbers representing centimeters. The roman numerals in between the numbers often represent the level of accuracy of the measuring tape. The smaller the numerals, the more accurate the tape is. The tapes that don’t have these markings mean they have no level of accuracy.

The numbers in the left-hand corner represent the total length of the tape measure. It’s required by law.


The mysterious black diamond you see on this image are found at the 19-inch mark and they’re there for construction workers to make five trusses in an eight-foot space. Truss layouts or items are usually eight-feet in length and when you divide eight feet into five you get 19.2 inches.

The accuracy would be difficult to achieve without this black diamond. While they’re useless to the average joe, they come in very handy for construction workers….