Interpupillary distance (IPD)

Interpupillary distance, usually shortened to IPD, is the gap between the centers of your two pupils, measured in millimeters. In a VR headset each eye looks through its own lens, and the image is sharpest when the optical center of each lens sits right in front of the pupil. When the lens spacing does not match your IPD, the picture can look blurry at the edges, feel strained, or appear slightly out of scale.

Hardware and software IPD

Headsets handle IPD in different ways. Some, like the Meta Quest 3, let you slide the lenses continuously with a wheel. Others, like the Meta Quest 3S, offer a few fixed lens positions. Headsets with eye tracking can measure your IPD and guide you, or adjust the lenses automatically. The software side also uses your IPD to place the two virtual cameras so that depth looks correct.

Finding your IPD

An optician can give you your pupillary distance (PD), which is the same measurement. You can also ask a friend to measure with a ruler, or use a phone app. Most adults land somewhere between the mid-50s and the mid-70s in millimeters, so check a headset's supported range before buying if your IPD is unusually narrow or wide.