👓 Reading Glasses Strength Calculator

Find the exact reading glasses power you need from your prescription — instant, free, no signup.

👓 Find Your Reading Glasses Power

Enter your Sphere (SPH) and ADD values from your glasses prescription. Both are on your prescription slip from your optometrist.

👁️ OD — Right Eye
D
D
👁️ OS — Left Eye
D
D
✅ Your Reading Glasses Powers
OD — Right Eye
Reading Power (D)
OS — Left Eye
Reading Power (D)

📊 Off-the-Shelf Reading Glasses Strength Guide

PowerWho it's forTypical age
+1.00Very mild reading difficulty40–45
+1.25 / +1.50Mild near vision loss45–50
+1.75 / +2.00Moderate presbyopia50–55
+2.25 / +2.50Stronger reading needs55–60
+2.75 / +3.00Advanced presbyopia60–65
+3.25 and aboveSevere near vision loss65+

🎉 Know your reading glasses strength? Shop the best reading glasses online!

🛍️ Shop Reading Glasses by Strength
⚠️ Medical Disclaimer:

All tools on PDCalculator.net are for educational and informational purposes only. They do not replace professional eye care advice, diagnosis, or treatment. Always consult a licensed optometrist or ophthalmologist before purchasing eyewear or making any changes to your vision correction. Results are based on standard optical formulas and are provided as a general guide only.

📋 How Reading Glasses Power is Calculated

Reading glasses power is simply the sum of your distance prescription (SPH) and your ADD value. The ADD is the extra magnification your doctor prescribes for reading close-up text.

// Formula: Reading Power = SPH + ADD
Example 1: SPH −1.00 + ADD +2.50 = +1.50 reading glasses
Example 2: SPH 0.00 + ADD +2.00 = +2.00 reading glasses
Example 3: SPH +0.50 + ADD +1.75 = +2.25 reading glasses
📋

What is SPH?

Sphere — your distance vision correction. Negative = nearsighted. Positive = farsighted. Zero means no distance correction needed.

What is ADD?

Addition — extra magnification for close-up reading, usually between +1.00 and +3.50. Found on bifocal and progressive prescriptions.

👓

Off-the-Shelf vs Custom

Pharmacy reading glasses are one power for both eyes. If your eyes differ significantly, get custom prescription readers.

❓ Frequently Asked Questions

My prescription doesn't have an ADD value — what do I do? +
If your prescription has no ADD value, it's a single vision distance prescription. You may not need reading glasses yet, or your optometrist prescribed separate reading glasses. Ask your optometrist to measure your ADD if you're struggling to read up close.
My two eyes have different powers — can I use off-the-shelf reading glasses? +
Off-the-shelf reading glasses have the same power in both lenses. If your OD and OS reading powers differ by more than 0.50D, you'll get better results with custom prescription reading glasses from an optometrist.
Why is my reading power positive even though I'm nearsighted? +
This is very common! Even nearsighted people develop presbyopia (age-related near vision loss). Adding the ADD to a negative SPH often results in a positive or lower-minus reading power, meaning you need some magnification for reading.
Can I buy reading glasses online with this result? +
Yes, for standard off-the-shelf readers. Just use the average of your two eye powers and pick the nearest available strength (usually in 0.25D steps). Visit our shop for recommended online retailers.
Do reading glasses prescription results expire? +
Prescriptions are typically valid for 1–2 years depending on your country. If your prescription is older than this, see your optometrist for an updated exam before ordering new glasses.