Snellen Visual Acuity to Decimal Conversion

Converts Snellen visual acuity fractions (20/20, 20/40, 20/200, etc.) to decimal notation and LogMAR values. 20/20 = 1.0 decimal = 0.0 LogMAR; 20/40 = 0.5 = 0.3 LogMAR; 20/200 = 0.1 = 1.0 LogMAR. Used to standardize acuity reporting across international systems.

Weight
Height
Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
Advertisement

How It Works

Converts Snellen visual acuity fractions (20/20, 20/40, 20/200, etc.) to decimal notation and LogMAR values. 20/20 = 1.0 decimal = 0.0 LogMAR; 20/40 = 0.5 = 0.3 LogMAR; 20/200 = 0.1 = 1.0 LogMAR. Used to standardize acuity reporting across international systems

Each component has a specific meaning:

  • International systems — The international systems recorded for the scenario being assessed.

Note: Interpret the snellen to decimal result against the thresholds and context described above.

How to Use

Enter the international systems for the scenario you are assessing. Converts Snellen visual acuity fractions (20/20, 20/40, 20/200, etc.) to decimal notation and LogMAR values. 20/20 = 1.0 decimal = 0.0 LogMAR; 20/40 = 0.5 = 0.3 LogMAR; 20/200 = 0.1 = 1.0 LogMAR. Used to standardize acuity reporting across international systems. Use the snellen to decimal result to inform your calculation.

Related Calculators

IOP Interpretation

Medical

Cup-to-Disc Ratio

Medical

Frequently Asked Questions