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How to Measure Your Pupillary Distance (PD)

Updated
Pupillary Distance (PD) is the distance between the centers of your pupils, measured in millimeters (mm). It helps ensure that your prescription lenses are properly aligned with your eyes.
 
For the most accurate result, we recommend having your PD measured by an eye care professional or optical store. If your eyeglass prescription does not include your PD, you may also measure it yourself by following the steps below.
 

1. Before You Start

You will need:
  • A millimeter ruler
  • A mirror
  • Good lighting
For better accuracy, keep your head level and look straight ahead while measuring. We recommend repeating the measurement several times to make sure you get a consistent result.
 

2. How to Measure Total PD

Total PD is the distance from the center of one pupil to the center of the other pupil.
 
Step 1: Stand in Front of a Mirror
Stand in front of a mirror at a comfortable distance. Keep your head straight and look directly ahead.
 
Step 2: Position the Ruler
Hold a millimeter ruler horizontally across the bridge of your nose. Align the 0 mm mark with the center of one pupil.
 
Step 3: Measure to the Other Pupil
Without moving your head, note the measurement that lines up with the center of your other pupil.
This number is your Total PD.
For example: PD: 63 mm means the distance between the centers of your two pupils is 63 mm.
 
Step 4: Repeat the Measurement
Measure your PD several times to make sure the result is consistent.
For example, if your measurements are:
  • 63 mm
  • 63 mm
  • 62.5 mm
Your PD is approximately 63 mm, as this is the value that appears most consistently. If your measurements vary significantly, we recommend having your PD measured by an eye care professional.
 
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3. Tips for Measuring PD

  • Keep Your Head Straight: Keep your head level and look straight ahead while measuring. Avoid tilting or turning your head.
  • Look at Your Reflection: Focus on your own eyes in the mirror rather than looking down at the ruler. Looking down can change your eye position and affect the measurement.
  • Measure Several Times: Repeat the measurement several times. If you get different results, continue measuring until you obtain consistent readings.
  • Ask for Professional Help: If you're unsure about your PD or have any questions, consult your eye care professional. An accurate PD measurement helps ensure that your prescription lenses are properly aligned with your eyes.
  • Consider Monocular PD: The method above measures Total PD, which is the distance from the center of one pupil to the center of the other. For prescription lenses, your eye care professional may also measure monocular PD—the distance from the center of each pupil to the centerline of the frame. This can help achieve more precise lens positioning.
 
 
 
 
 
 

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