Pupillary distance calculator: measure your PD in under a minute.

Pupillary distance (PD) is the distance in millimeters between the centers of your two pupils. It sounds like a small thing, and it is — most adults measure somewhere in the mid-50s to low-70s, with around 63 mm being typical. But that small number decides where the optical center of each lens sits in your frames. Get it right and the lenses disappear from your awareness. Get it wrong by a few millimeters and you can end up with eye strain, or glasses that never feel quite right.

Here's the frustrating part: PD often isn't printed on your prescription. Optometrists measure it during the exam, but it doesn't always make it onto the paperwork, and plenty of online glasses retailers leave a blank field and expect you to fill it in. That's the gap this pupillary distance calculator fills. You get the number in about a minute, at home, without booking anything or paying anyone.

Every prescription lens has one exact point where vision is clearest — the optical center. The lab grinding your lenses uses your PD to place that point directly in front of each pupil. If the placement drifts, you're effectively looking through the lens off-axis, which acts a bit like an unwanted prism. Mild prescriptions tolerate a little error. Strong ones and progressive lenses don't.

So when people ask what is my PD for glasses, the practical answer is: whatever gets the optical center lined up, measured rather than guessed. A proper pupillary distance tool costs nothing and removes the guesswork. Compared with the cost of remaking a pair of lenses, a minute of measuring is an easy trade. If you're curious how the measurement works, we explain the method on the about page.

Retailer order forms ask for one of three formats, and they're all the same underlying measurement described differently.

Total PD is a single number, pupil to pupil. Dual PD gives two numbers, each measured from the center of your nose bridge to one pupil. The two sides of your face rarely match exactly, which is why dual PD is worth using when a form offers it — and it's what progressive lens orders usually want. Near PD is a slightly smaller number used for reading glasses, typically about 3 mm less than your distance PD, because your eyes converge when you focus up close.

Our tool returns all three at once, so one measurement covers every form field you'll meet. Buying readers? Use the near PD calculator value. Ordering progressives with separate right and left fields? Use the dual PD. If you're doing your PD measurement for glasses online, the result card is formatted to match typical checkout forms, so you can copy the numbers straight across.

To measure pupillary distance accurately at home, you mainly need to control three things: head position, card position, and lighting. A level head and a flat card get you close to an optician's reading — good enough for most single-vision orders. The camera method has one extra advantage — it averages multiple frames, so a single blink or slight drift doesn't skew the result.

If the tool reports low confidence, don't ship the number — retake it in better light. And a note on limits: for very strong prescriptions, progressives, or prism corrections, it's still worth asking your optician to confirm the measurement during your next exam.