Home / Free PD Measurement Tool
Free Tool — No Sign-Up Required
Measure Your PD at Home
In 30 Seconds

Your pupillary distance (PD) tells your lenses exactly where to focus. Use your phone camera to measure it free — no ruler, no optician visit needed.

⚡
Free & Instant
No cost, no app, no account
🔒
Private & Secure
Camera never leaves your device
👓
Prescription Ready
Works with any online glasses order
Shade Gray · Free Tool

Measure Your PD

Use your camera to get your pupillary distance in about 10 seconds — no tools needed.

Remove your glasses before starting
Face a window or bright lamp for even lighting
Hold your device at eye level, ~40cm away
Look straight at the camera — no tilting

Loading face detection…
First load takes ~10 seconds

Position Your Face

Fit your face inside the oval and look straight at the camera

3
Align face
Looking for face…
Total PD
–
mm
Right / Left
– / –
mm

Your PD Measurement

Enter these values when ordering prescription glasses online.

Total Pupillary Distance
–
mm
–
Right PD (OD)
–
Left PD (OS)
Accurate to ~1mm. For high-power prescriptions (±4.00 or stronger), confirm your PD with your optician.
Ready to order? Try frames at home first.
Pick 5 frames, wear them 5 days — free shipping both ways.
Free Home Try-On

Camera Not Available

Please allow camera access and reload.

Enter PD manually instead: Average adult PD is 63mm. Your optician can measure it for free, or check your prescription slip.
What is Pupillary Distance?

Pupillary distance (PD) is the distance in millimeters between the centers of your two pupils. When your lenses are made, this number tells the lab exactly where to position the optical center so your vision is sharp and comfortable.

Getting your PD wrong by even 2–3mm can cause headaches, eye strain, and blurred vision — especially with stronger prescriptions. Most adults measure between 58mm and 72mm, though this varies with face width.

A dual PD (e.g. 32 / 32) splits this into right and left eye measurements separately and is more precise. Our tool measures both at once.

Tips for an Accurate Reading
1
Face the camera straight on

Hold your phone at eye level, about 30–40cm away. Tilting up or down introduces error.

2
Use good lighting

Natural or bright indoor light works best. Avoid backlighting or dim rooms.

3
Remove glasses if wearing any

Frames block iris detection and affect accuracy.

4
Hold still until the ring fills

The tool averages multiple frames over ~2 seconds. A steady hold gives the most accurate result.

Not sure which frame size fits? After getting your PD, use our free Home Try-On to test 5 frames at home before you buy. Free shipping both ways, no credit card held.
Frequently Asked Questions
What is pupillary distance (PD)? +
Pupillary distance is the measurement in millimeters between the centers of your two pupils. Lens makers use this number to center each lens in front of your eye, ensuring sharp and comfortable vision at all distances.
How accurate is this tool? +
Results are typically within 1mm of a professional measurement — accurate enough for most prescription glasses. For high-power prescriptions (over ±4.00), confirming with your optician is recommended.
Do I need a ruler or credit card? +
No. Our tool uses your iris diameter as a built-in calibration reference (the average human iris is 11.8mm), so it calculates real-world distances without any physical object.
What's the difference between single PD and dual PD? +
A single PD (e.g. 64mm) is the total distance between both pupils. A dual PD gives separate right (OD) and left (OS) values — for example 32.5 / 31.5. Dual PD is more precise and particularly useful for progressive lenses. Our tool measures both.
Where do I enter my PD when ordering from Shade Gray? +
After adding a frame to your cart and selecting your prescription, you'll see a field for PD. Enter your total PD or toggle to dual PD to enter right and left values separately. Your result from this tool can be used directly.
Is my camera footage stored or shared? +
No. Face detection runs entirely in your browser — nothing is sent to any server. Your camera feed is never recorded, stored, or shared.
Prescription Glasses From $49

Wide & Extrawide sizes available. Free shipping & returns. FSA/HSA accepted.

More Helpful Guides