5 Ways to Measure Your Pupillary Distance (PD) at Home

Last Updated on February 24, 2021 by Tony Parrish

Pupillary distance (PD) is a necessary measurement when ordering glasses online. Many opticians neglect to give this simple measurement to their patients, but it’s quite easy to determine on your own at home. We have put together at least 5 easy ways to measure your PD at home with simple tools, including your smartphone.

What is Pupillary Distance (PD)?

Pupillary distance is the measurement of the distance from the center of one pupil to the other. Finding this measurement simple but also very crucial when shopping for new prescription glasses online. A correct PD measurement ensures that the lenses optical center is correctly positioned over your pupil.


What is Dual Pupillary Distance (PD)?

In instances where your eyes aren’t perfectly symmetrical, you can measure the distance from the center of your nose (bridge) to the center of each eye to get your dual pupillary distance. In instances like this, a dual PD measurement will typically result in a better fitting lens due to each eye having its exact pupillary distance. This puts the lens optical center in the correct position for each eye.


How to Measure Your Pupillary Distance (PD) at Home

1.) How to Measure Your PD Online

Technology can be a beautiful thing, and that is indeed the case when using Warby Parker’s pupillary distance measurement tool. All you need is a card with a magnetic strip (credit, debit, gift, library card, etc.) and a webcam. Since most, if not all computers on the market come with a webcam, this shouldn’t be an issue for most.

We found their PD tool to be very accurate but still ran through it a few times to get a more precise PD measurement. The best part? You can use this tool to determine your PD whether you buy your next glasses from Warby Parker or not!

2.) Measuring Your PD With Your Smartphone

We know not everyone may have access to a millimeter ruler or a printer, especially if you aren’t home. Because of this, we have created a simple way to use your smartphone as a PD ruler.

  1. To start, open our guide on how to measure your pupillary distance with your smartphone.
  2. Once you have the smartphone document open, use the credit card outline or the penny outline to scale your ruler correctly. Just get either guide within view on your screen and lay the appropriate object (credit card or penny) on the screen to scale the page.
  3. Once you have the scaling dialed in you can proceed to measure your PD with a mirror as outlined in the steps below (option #3) or on the guide.

Assuming you scale the ruler correctly, this method should be just as accurate as using an actual ruler.

3.1 ) Measure Pupillary Distance (PD) With A Ruler

  1. Find a ruler that measures in millimeters (mm) or download our ruler here.
  2. Stand 8-10 inches away from a mirror, looking straight ahead with the ruler parallel above your eyes. Rest the ruler against your forehead for stability.
  3. Line up the zero (0) on the ruler with the center of your right pupil. Close your left eye to ensure that the ruler is lined up perfectly with the center of your right pupil.
  4. With the zero now centered with your right pupil, close your right eye to measure where the center of your left pupil aligns on the ruler.
  5. That measured distance is your PD measurement! Repeat these steps a few times to ensure you have measured as accurately as possible.

    It will be easier to measure your pupillary distance if you ask someone around to help. If you go this route, just stand in front of your friend or family member while looking at a point in the distance straight in front of you. They can then walk through steps 3-5 to help determine your PD measurement.

3.2) Dual Pupillary Distance (PD) With A Ruler

If you think you may benefit from a dual PD measurement, you can repeat the steps above only this time using our dual PD ruler.

Our dual PD ruler allows you to center it down the middle of your nose making it easy to measure the specific pupillary distances for both your left and right pupils. The process is nearly identical to measuring for a single PD, and you can follow the 5 simple steps on our guide to help you get started!

Many online retailers can create lenses with dual PD’s and doing so will provide a better fit and optics for you!

4.) How to Measure Pupillary Distance Using Old Glasses

If all else fails, you can use your old or current glasses to measure your pupillary distance. This will likely be the least accurate solution, but you should be able to get a reasonably precise read. Follow these easy steps below:

  1. With your glasses on, stand 8-10 inches away from a mirror.
  2. While staring straight ahead, take a non-permanent marker to mark the center of your pupils on your glasses. Try using a highlighter, dry erase, or washable marker. Be sure to keep Sharpies or anything permanent far away from your lenses!
  3. Remove your glasses and measure the distance between the dots to get your PD measurement.
  4. Again, this method will be the least accurate of the bunch, but you can gain more accuracy if you have someone else make the marks on your lenses for you. Again, recommended markers to use are dry erase, highlighters, or and washable marker.

5.) Ask Your Optician For Your Current PD Measurement

Okay, this isn’t really a way to measure your PD at home, but you should be able to accomplish this with a simple phone call. Measuring your pupillary distance is a standard part of any eye exam. If you have been to an optician in the past and ordered glasses through them, they have your PD measurement on file. Just call their office, request your PD and be on your way!

Sounds simple right? Unfortunately, this simple task can be challenging for some people to accomplish depending on how their opticians or eye doctors feel about ordering glasses online. Many people have even had their opticians all but refuse to hand over their PD!

Thankfully, the law is on your side in most states. The Federal Trade Commission highly recommends opticians to provide their patients with their PD measurement hassle free. In some states, the law requires that they must! They must also provide you with your prescription upon request free of any fees outside of the initial exam.