What the numbers on your prescription mean
Learn what each number means, check that you copied it right, and see which lenses fit it. Then measure your PD at home with a ruler.
This is a sample. Hover over or tap any column to see what it means.
Eyeglass prescription
| −2.25 | −0.75 | 180 | +1.75 | — | |
| −2.00 | — | — | +1.75 | — |
63
SPH
Sphere
The main power of the lens, in diopters.
Understand my prescription
Enter the numbers from your paper. We show them back with every sign spelled out, then explain what they mean and which lenses fit.
Stays on your device. Nothing you type here is sent or saved.
- 1Enter
- 2Check signs
- 3Read
Do the signs match your paper?
A plus (+) and a minus (−) make opposite lenses. Compare each value with your prescription, one by one.
Ways to give us your prescription
When you order glasses, pick the way that is easiest for you. We only make your lenses once we have your prescription.
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Type it in
Enter the numbers from your paper in the lens step, with the same fields as the tool above.
When you order
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Upload a photo
Take a clear photo of the whole prescription. An optician reads it and checks it against your order.
Available when the store opens
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We contact your eye doctor
Give us your doctor’s name and phone number. We request your prescription from their office.
When you order
- Your prescription must be valid and not expired. Check the date on it.
- We don’t do eye exams. If yours has expired, see an eye doctor for a new one first.
- A contact lens prescription can’t be used for glasses. They are different prescriptions.
Measure your PD
PD (pupillary distance) is the space between the centers of your pupils, in millimeters.
With a mirror
- Stand about 8 inches (20 cm) from a mirror, in good light.
- Close your right eye. Line up the ruler’s 0 with the center of your left pupil.
- Close your left eye, open your right, and read the mark at the center of your right pupil.
- Repeat three times and use the average.
With a friend
- Sit face to face at the same height, about an arm’s length apart.
- Look past your friend at something at least 10 feet (3 m) away.
- Your friend lines up 0 with the center of one pupil and reads the mark at the other.
- Measure three times and use the average.
- 50–75mm
- Typical adult rangeThe average adult measures about 63 mm. Kids measure less.
- 63
- Single PDOne number: the whole distance from pupil to pupil.
- 31.5 / 31.5
- Dual PDTwo numbers, one per eye, from the center of your nose to each pupil.
Two numbers like 63/60 on a prescription usually mean distance and near PD, not right and left.
Educational information, not medical advice
This page explains prescriptions in general. It is not an eye exam or a diagnosis. Our optician verifies every prescription before we make your lenses.
Questions? Contact us