Prescription Swim Goggles - Dioptre Calculation Tool
Find Your Swim Goggle Diopter Strength
Use your glasses prescription to estimate the ready-made prescription swim goggle lens strength you may need. Enter your Sphere and Cylinder values for each eye below.
How It Works
- 1Find the Sphere / SPH and Cylinder / CYL values on your glasses prescription.
- 2Use the formula: Sphere + (Cylinder ÷ 2).
- 3Choose the closest available ready-made goggle lens strength. Many optical swim goggles come in 0.50 diopter steps.
Need Prescription Goggles?
Browse our prescription swim goggles or contact Swimwear Shack for help choosing the right model.
Shop Prescription GogglesWhat does diopter mean?
A diopter is the lens strength used to correct vision. Prescription swim goggles usually use ready-made spherical lens powers rather than custom lenses.
Do prescription swim goggles correct astigmatism?
Most ready-made prescription swim goggles correct sphere only. They do not fully correct cylinder or axis. Mild astigmatism may still be manageable, but higher astigmatism may require custom-made prescription goggles.
Should I choose the same strength for both eyes?
Only if your right and left prescription calculations are the same or very close. Some goggles allow separate right and left lens strengths, depending on the model.
Can I wear contact lenses under swim goggles?
It is generally not recommended because pool, ocean and lake water can increase the risk of eye infections when trapped behind contact lenses. Ask your optometrist for personal advice.