How to Measure Your Frame Size

Eyeballing Your Eyeglasses: A Visual Guide to DIY Frame Measurement

In the old days, when you used to pay steep prices to buy glasses from the local optical store, you could try them on to see how they fit. Buying glasses online is uncharted territory for many, but there's no need to worry! 

The good news is that it's easy to find your frame measurements to ensure you're getting the right fit. The better news is you're going to save a bundle ordering glasses from Seesee.

Follow the handy guide below to measure your glasses and make shopping easy!

Once you find your frame measurements, you can browse our selection, find the style you want, and order the perfect pair of glasses.

A Guide to Eyeglasses Frame Measurements

What Are The Frame Dimensions?


measures the entire horizontal front of the frame, from the furthest extended point on either side.


is the vertical height of the lens.


is the part that goes across the bridge of your nose—hence the name.


connect to the front of the frame on either side and rest behind your ear.


is the horizontal diameter of one lens. Doctors may refer to this as “eye size.”


A Helpful Hint

You’re ahead of the game if you already have a pair of eyeglasses that fits you well. Your glasses may have numbers, which indicate three frame dimensions, printed on the inside of the temple arm.


If the numbers are 54-18-140, your frame dimensions are:

54 mm lens width 

18 mm bridge width 

140 mm temple arm length

You have a leeway of 2-3 mm on each measurement, except for the bridge. Stick to a leeway of just 2 mm on the bridge.

The most important dimension— the frame width—will not be printed on the temple arm. Follow our guide below to measure the frame width and ensure your new glasses are the right size for your face.

DIY Measurements

If the numbers aren’t printed on your glasses, never fear. You can measure your frame dimensions with a millimeter ruler or cloth measuring tape.


Measure horizontally across the entire front of the frame. Include any lug or hinge pieces that stick out on the sides.


Measure the lens vertically, at its tallest point. For bifocal or progressive prescriptions, the lens height must be at least 30 mm.


Measure horizontally, at the top of the bridge, from the edge of one lens to the other.


Measure from the hinge—where the arm connects in the front— to the spot where the arm begins to bend down around the ear. Then measure from the top of the bend to the bottom tip. Add the two sections together for the total temple arm length.


Measure the lens horizontally, at its widest point. Make sure the lens width accommodates your pupillary distance so that your eyes align with the “optical center” of the lens. Measure your PD using this guide 

Keep In Mind

+/- 6.00

If the SPH on your prescription is +/-6.00, it’s best to stick with lens widths lower than 50 mm. This will keep your lenses thinner.

Once you have the measurements for your frame dimensions, shop to your heart’s desire and find that perfect pair of glasses online!

In addition to measuring your eyeglasses, try utilizing virtual try-on options like Seesee Frame Fit® to help to ensure you pick a frame that will fit your face.