What do the numbers on the inside of glasses frames mean?

Do you ever wonder about the weird numbers on your glasses? You’ll notice a number like 51-16-142 printed on the inside of the frames. You might think of it as a normal number but it says a lot about your glasses dimensions.

These numbers denote three vital pieces of information about your glasses frame size. Here’s our simple frame size guide to help you comprehend easily.

Lens Diameter - It represents the horizontal width of the lenses. A normal lens diameter falls in the range of 40mm to 62mm.

Bridge Width -It suggests about the distance of the lenses and the size of the nose bridge of the frames. A normal bridge width ranges from 14mm to 24 mm.

Arm’s Length - It’s the measurements of the temple length, starting from the hinges to the end of temple tips. A normal arm length ranges from 120mm to 150mm.

Which are all measured in millimetres.

For eg, the first number (51 mm) tells about the lens diameter. The second number (16 mm) informs about the bridge width while the last number (142 mm) states the arm length.

Apart from these measurements, you’ll find a model no. of the product alongside the frame dimensions which is something usually like YC-A21026. It denotes the model no. or a SKU of the product.

Check out our article on pupillary distance.