PD Ruler Printable

This PD ruler printable is a 100 mm strip with a mark at every millimeter, drawn in your browser and ready to print on any home printer. A second line below it is exactly as long as a bank card is wide, so you can prove your printout is true size before you measure anything. No photo is needed and nothing is uploaded. It is a convenience for a rough pupillary distance, not a replacement for the measurement an optician takes for prescription lenses.

How the PD ruler printable is built

The ruler is an SVG image sized in millimeters, which means a printer set to actual size draws 100 mm as 100 mm. Numbers appear every centimeter, a medium mark every 5 mm and a short mark at each millimeter. Pupillary distance is the gap between the centers of your pupils, and adult values are usually somewhere between the mid 50s and low 70s of millimeters, so 100 mm gives plenty of room.

Below the ruler sits an 85.6 mm line with a small end mark on each side. That is the width of a standard bank card, as set by the ISO 7810 ID-1 size used for credit cards, debit cards and most driving licences. It gives you a quick check that needs no other ruler.

Calibrate the PD ruler printable with a bank card

Printers often shrink pages to fit, and a shrunk PD ruler printable gives a wrong answer without looking wrong. Check it every time you print.

1. Print the page at 100% or Actual size. Turn off Fit to page, Scale to fit and Shrink oversized pages.
2. Lay a credit or debit card along the lower line, lining up the left edge with the left mark.
3. If the right edge of the card lines up with the right mark, the ruler is true size.
4. If the card is longer than the line, the print is too small; if it is shorter, the print is too large.
5. Type the printed line length into the box above if you have another ruler, and the page works out the print scale to use.

For example, a line that measures 82.0 mm needs a scale of about 104.4%, because 85.6 divided by 82.0 is 1.044. Reprint at that setting and check again.

How to measure pupillary distance with the PD ruler printable

Use a mirror, or ask a friend to hold the ruler. The mirror method works like this:

1. Stand about 20 cm from a mirror in even light and hold the printed ruler flat against your brow.
2. Look straight ahead at your own reflection and close your right eye.
3. Line up the zero mark with the center of your left pupil.
4. Open your right eye, close your left, and read the number at the center of your right pupil without moving the ruler.
5. Repeat three times and take the middle value.

A friend can use the PD ruler printable more accurately, because you stay still while they read the number from a short distance. The pupil is dark, so a small flashlight held under the ruler can help you see its center. Look at a point far away rather than at the mirror to keep the eyes parallel.

What a PD ruler printable cannot do

Even a perfect PD ruler printable only measures your pupils as they appear. It does not give the separate left and right distances from the nose, which opticians call monocular PD, and it does not give the near PD used for reading glasses. Progressive and high-index lenses can also require the height of the pupil in the frame. Parallax from reading the ruler off-center adds another millimeter or two.

For glasses you plan to wear, an optician or the shop making the lenses should confirm the value. Do not order prescription lenses from this ruler alone. Treat it as a quick check for curiosity, for a sanity check on a number you have been given, or for frames that do not hold a prescription.

Printer problems with a PD ruler printable

• Browser header and footer. Turn them off in the print dialog so the page margin does not move the ruler.
• PDF viewer scaling. If you save to PDF first, open it at 100% and print at Actual size.
• Phones and tablets. Many mobile print dialogs scale to fit. Use a desktop browser if the card check fails.
• Paper size. A4 and Letter both hold the 100 mm strip, so no setting is needed beyond scale.

Cut the strip along its edge or fold the paper so the PD ruler printable lies flat against the face.

A photo estimate instead of a PD ruler printable

If you do not want to print anything, the measure pupillary distance online tool estimates PD from a single front photo, using the visible iris width as a scale, and shows a plus-or-minus range. It is less precise than a good ruler used well, but it needs nothing printed. For frame choices once you have a number, read glasses for face shape.

PD ruler printable FAQ

Is a PD ruler printable accurate?

It can be accurate to a millimeter or two if you print at actual size and pass the bank card check. It is not a substitute for an optician's measurement.

Can I order glasses online with this PD ruler printable?

Only for frames without a prescription, or as a rough check. Prescription lenses need a measurement from a professional.

Why does my PD ruler printable not match a real card?

The printer or browser scaled the page. Print again at 100% or Actual size, or use the scale the page suggests.

What is a normal PD?

Adult PD commonly falls in the mid 50s to low 70s of millimeters. Differences between people are normal.

What is the difference between PD and monocular PD on a PD ruler printable?

PD is the total distance between the pupils. Monocular PD is the distance from the nose bridge to each pupil, and the two numbers can differ.

Does this page store or upload anything?

No. The ruler is drawn in your browser and no photo is needed.