20/20 Vision Calculator: Convert Eye Prescription to Visual Acuity

Your details

Choose which eye(s) to include. "Both" shows right and left side by side.
The sphere power from your right-eye prescription. Negative = nearsighted; positive = farsighted.
D
The cylinder (astigmatism) correction for your right eye. Enter 0 if your prescription has no cylinder.
D
The sphere power from your left-eye prescription. Negative = nearsighted; positive = farsighted.
D
The cylinder correction for your left eye. Enter 0 if none.
D
When on, the cylinder diopters are weighted at 50% and added to the sphere for a more realistic acuity estimate.
Right eye Snellen (20/x)Significant reduction
20/125

Estimated uncorrected visual acuity for the right eye in 20/x notation

Left eye Snellen (20/x)20/125
Right eye LogMAR0.8
Left eye LogMAR0.8
Right eye decimal0.16
Left eye decimal0.16
Right eye metric (6/x)6/38
Left eye metric (6/x)6/38
OD Snellen denominator125
OS Snellen denominator125
OD effective diopters-2.25
OS effective diopters-2.13
125 Snellen denom.
20/20-25 Normal<2520/32-80 Mild-moderate25-8020/100-200 Significant80-20020/250-500 Severe200+

Your right eye prescription of -2.00 D gives an estimated acuity of 20/125.

  • Right eye (OD): estimated uncorrected acuity is 20/125 (significant reduction).
  • Left eye (OS): estimated uncorrected acuity is 20/125 (significant reduction).
  • Most US states require at least 20/40 corrected vision to hold a standard drivers license. Uncorrected acuity worse than 20/40 does not necessarily disqualify you if corrective lenses bring it to the legal standard.
  • These estimates are approximations based on your prescription diopters. Actual acuity also depends on astigmatism axis, corneal health, pupil size, and lighting. Only a clinical refraction with an eye chart gives a precise measurement.

Next stepA comprehensive eye exam from an optometrist or ophthalmologist will give you an accurate Snellen acuity measurement and confirm whether your prescription is current.

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