How to Measure Glasses Frame Size & PD (Complete Step-by-Step Guide)

When you used to pay expensive 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! It's very easy to find your frame measurements to ensure you're getting the right fit. And you're going to save a bundle by ordering glasses from Mozaer.

Quick Summary
  • Frame size is based on lens width, bridge width, and temple length (e.g., 52-17-140).
  • PD (pupillary distance) helps center your lenses correctly for clear vision.
  • Dual PD measures each eye separately for higher accuracy in some cases.

Download Our Free Printable PD Ruler (PDF)

Don't have a ruler? Download and print our accurate PD ruler here.

⬇ Download Free PD Ruler (PDF)
Important printing instructions:
  • When printing, choose “Actual size” or set scaling to 100% (Do not scale / No fit-to-page).
  • Use a credit card to verify the calibration box on the PDF before measuring.
  • If the calibration box does not match your card, reprint with correct settings.

 

1. About the frame size you should know.

 

 

2. How to find out your glasses measurements?

 

 

1)、Primary Way Measurements - Frame Width

 

Frame width is the entire horizontal front of the frame, from the furthest extended point on either side. (Note: You will not find this number on your glasses.)     

 

 

 

2)、Other Way Measurements

 

If you already have eyeglasses, find the measurements on the inside of the temple arm or demo lens such as  52-17-140  (means lens width is 52mm, bridge is 17mm, temple length is 140mm ), you can compare it to the measurements. However, we still recommend measuring the Frame Width to choose the right eyeglasses frame.

Number Meaning Typical Range (mm)
Lens Width Horizontal width of one lens 40–60
Bridge Width Distance between the lenses 14–24
Temple Length Length of the arm from hinge to ear 120–150
Glasses frame size measurements diagram showing lens width bridge width and temple length
Frame size diagram: lens width, bridge width, and temple length.
Hands measuring glasses frame width with a millimeter ruler
Example: measuring frame width using a millimeter ruler.

 

 

 

3)、Tips for Choosing Comfortable Lenses
 
(1) For bifocal or progressive prescriptions: the lens height of frame must be 35mm or greater.
(2) If SPH on your prescription is +/-6.00 or greater, choose a frame with lens width lower than 50mm, and choose high-index lens.

How to Measure Your PD (Pupillary Distance)

Pupillary distance (PD) is the distance between the centers of your pupils. Accurate PD helps your lenses align correctly with your eyes for clear, comfortable vision.

Step-by-Step: Measuring PD at Home (Mirror Method)

  1. Stand about 8 inches (20 cm) away from a mirror.
  2. Hold a millimeter ruler flat across your brow.
  3. Close your right eye and align the ruler’s 0 with the center of your left pupil.
  4. Open your right eye and close your left eye.
  5. Read the mm mark aligned with the center of your right pupil. That’s your single PD.
Measuring pupillary distance at home using a ruler and a mirror
Measuring PD at home using a ruler and a mirror.

How to Measure Dual Pupillary Distance

Dual PD (also called monocular PD) measures each eye separately. It’s written as two numbers, such as 32/30.

  • Measure from the center of your nose bridge to the center of your right pupil.
  • Measure from the center of your nose bridge to the center of your left pupil.
Dual pupillary distance measurement showing nose bridge to each pupil
Dual PD: measure from the center of the nose bridge to each pupil.

Average Pupillary Distance Ranges

Group Average PD (mm)
Adult Men 54–74
Adult Women 52–70
Children 43–58

Frequently Asked Questions

How to measure PD at home?

You can measure PD at home using a ruler and a mirror by measuring the distance between the centers of your pupils.

How to measure dual pupillary distance?

Measure from the bridge of your nose to each pupil separately to get dual PD.

How do you measure glasses frame size?

Glasses frame size is based on lens width, bridge width, and temple length (often printed inside the temple arm).

How to measure spectacles size?

“Spectacles size” means the same as glasses frame size—measure lens width, bridge width, and temple length.