Vision Calculator

Vision Test Type:

Numerator (Distance You Stand):

Denominator (Line You Read):

Eye Tested:

With Correction:

The Vision Calculator is an easy-to-use tool that helps you assess your visual acuity using common eye test notations. Whether you’re testing your eyesight at home or comparing professional results, this calculator provides instant Snellen, Decimal, LogMAR, and percentage conversions. It also categorizes vision quality and legal status.

How the Vision Calculator Works

Choose Vision Test Type
Select between Snellen (20/20), Decimal, LogMAR, or Percentage based on your test format.
Enter Distance and Line Read
Input the numerator (distance you stand, typically 20 feet) and denominator (the line you can read on the chart).
Select Eye Tested
Choose Right Eye (OD), Left Eye (OS), or Both Eyes (OU).
Specify Correction
Indicate if you are using corrective lenses (Yes) or testing uncorrected vision (No).
Click Calculate
The calculator will display:
- Snellen Notation: e.g., 20/20
- Decimal Notation: e.g., 1.0
- LogMAR: logarithmic scale for visual acuity
- Visual Acuity Percentage: e.g., 100%
- Vision Category: Normal, Near Normal, Mild Loss, etc.
- Vision Quality: Excellent, Good, Fair, Poor
- Legal Status: Normal, Vision Impaired, Legally Blind

Example: Calculating Your Vision

Suppose you stand 20 feet from the chart and can read the 40-foot line:

Snellen Notation: 20/40
Decimal Notation: 0.5
LogMAR: 0.30
Visual Acuity %: 50%
Vision Category: Mild Vision Loss
Vision Quality: Good
Legal Status: Normal

This result indicates mild vision loss, but still within the normal legal limits for everyday activities.

Vision Categories Explained

Decimal	Category	Quality	Legal Status
≥1.0	Normal Vision	Excellent	Normal
0.8–0.99	Near Normal	Very Good	Normal
0.5–0.79	Mild Vision Loss	Good	Normal
0.3–0.49	Moderate Vision Loss	Fair	Vision Impaired
0.1–0.29	Severe Vision Loss	Poor	Legally Blind
0.05–0.09	Profound Vision Loss	Very Poor	Legally Blind
<0.05	Near Total Blindness	Minimal	Legally Blind

Tips for Accurate Results

Test Each Eye Separately: Always measure OD and OS individually, then OU for combined vision.
Use Corrective Lenses if Needed: Test both corrected and uncorrected vision for full assessment.
Maintain Proper Distance: Standard Snellen charts require 20 feet (6 meters) for accurate results.
Record and Track Results: Monitor changes over time to detect potential eye health issues early.

Why Use a Vision Calculator?

Home Eye Testing: Quickly assess your vision without professional equipment.
Track Vision Changes: Detect gradual deterioration or improvement in eyesight.
Convert Notations: Easily switch between Snellen, Decimal, LogMAR, and percentage.
Understand Legal Status: Determine if vision meets requirements for driving or other activities.
Educational Purposes: Learn more about how vision is measured and categorized.

Frequently Asked Questions

What is Snellen notation?
A visual acuity scale showing the distance you can see compared to a normal standard (20/20).
What is Decimal notation?
A decimal representation of visual acuity. 1.0 = 20/20 vision.
What is LogMAR?
Logarithm of the Minimum Angle of Resolution, commonly used in research and eye clinics.
How is visual acuity % calculated?
Decimal value multiplied by 100.
What does “Legal Status” mean?
Indicates if your vision meets normal or legally blind criteria.
Can I test both eyes at once?
Yes, OU (Both Eyes) measures combined vision.
Do I need glasses or contacts for testing?
You can test with or without correction to compare results.
What is considered normal vision?
Snellen 20/20, Decimal 1.0, or 100% visual acuity.
How often should I check my vision?
At least once a year, or more frequently if vision changes.
Is this a medical diagnosis?
No, this tool is for informational and educational purposes only.

This Vision Calculator provides a comprehensive, instant view of your visual acuity, categories, and legal status, making it perfect for home assessments, education, and historical eye test comparisons.