// Free Tool
Pupillary Distance (PD) Ruler
Measure your PD at home using a standard credit card as a calibration reference. Takes about 5 minutes with a mirror and a friend (or a steady phone).
Step 1
Calibrate your screen
Place a standard credit card (85.6mm × 54mm) horizontally on your screen below this ruler. Drag the slider until the white bar matches the width of your card exactly.
85.6mm
← Drag to match your card width →
Step 2
Measure your PD
Stand 40 cm (16 inches) from the screen. Look straight ahead at your own reflection. Drag the LEFT marker to your left pupil, and the RIGHT marker to your right pupil.
L
R
Your PD: — mm
Step 3
Single vs. Dual PD
Some prescriptions ask for right PD and left PD separately (measured from the nose center). Divide your total PD roughly in half; they're usually within 0–2mm of each other.
Total PDRight PD (est.)Left PD (est.)
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