Tool
PD Calculator
Already know your PD? Convert distance PD to near PD and single (total) PD to dual (monocular) PD in real time. No camera, no signup — everything runs in your browser.
PD Calculator
Inputs
Results
Near (total) PD
60.0 mm
Near PD subtracts the convergence offset from your distance PD because your eyes turn inward to focus up close. Dual values split from the total (or use your own R/L if entered).
How the PD calculator works
This pupillary distance calculator does the two conversions opticians use most. First, it turns your distance PD into a near PD for reading glasses by subtracting a small convergence offset — usually about 3 mm — because your eyes rotate inward when you focus on something close. Second, it splits a single (binocular) PD into dual PD, the left and right monocular values measured from the bridge of your nose, which matter for progressive and higher-powered lenses.
If your faces aren't perfectly symmetrical — most aren't — enter your real right and left values and the calculator keeps them; otherwise it splits the total evenly. Learn more about single vs dual PD, near PD for reading glasses, and the average pupillary distance.
A calculator only converts numbers you already have. If you don't know your PD yet, you can measure it for free and privately with your webcam, a photo, or our printable PD ruler — your image never leaves your device.