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Eyeglass frame sizes explained

Frame sizes: The numbers

Eyeglass frame sizes are indicated by three numbers stamped on the inside of your eyeglasses. These numbers usually appear on the inner surface of one of the frame temples that hold your glasses in place behind your ears.

Specifically, the frame size numbers of glasses are:

The key measurements that describe eyeglass sizes are the eye size, bridge width and temple length.

  1. The eye size

  2. The bridge size

  3. The temple length

All three frame measurements are specified in millimeters (mm).

For example, let’s say you see these three numbers on the inside of your frames: 48-19-140.

Eye size

The first number — the eye size — is the horizontal width of the lenses.

In this case, the openings in the frame for the lenses are 48 mm wide. Generally, the eye size of most frames will be 44 to 62 mm.

Bridge size

The second number — the bridge size — is the distance between the lenses.

In other words, it’s the size of the “bridge” of the frame that rests on your nose. In this case, the frame bridge is 19 mm wide. The bridge size of most eyeglass frames will be 14 to 24 mm.

Temple length

The third number — the temple length — is the length of the “arms” or “stems” of the frame.

Eyeglass temple size is measured from the hinge of the frame to the end tip of the temple. In this case, the temple length is 140 mm. Temple lengths generally range from 120 to 150 mm.

Other considerations

Often, a small square (rather than a dash) will separate the eye size and the bridge size on the frame.

In addition to the eye size, bridge size and temple length, you may see other numbers (or letters and names) stamped on the inside of the frame. These usually are the frame model and/or the color of the frame.

Be aware that two frames that have identical frame sizes may fit differently, depending on the style of the frame.

READ MORE about eyeglass sizes.

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