QR Code Best Practices

QR Code 크기 설정: 거리별 최소 크기

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Size formulas and lookup tables for scan distances from 10cm to 10m. Module size requirements for reliable scanning.

  
  

    
  








  
  

    
    
      
      
  1. 
        QR Code Sizing: Minimum Size for Every Distance
      
    2. 
      
      
  2. 
        The Formula
      
    3. 
      
      
  3. 
        Quick Reference Table
      
    4. 
      
      
  4. 
        Factors That Increase Minimum Size
      
    5. 
      
      
  5. 
        Factors That Allow Smaller Sizes
      
    6. 
      
      
  6. 
        Safety Margin
      
    7. 
      
      
  7. 
        Key Takeaways
      
    8. 
      
    

  









  
  

  
  

    
    

      
QR Code Sizing: Minimum Size for Every Distance


Getting the physical size right is essential for reliable scanning. Too small and the code will not scan from the intended distance. Too large and it wastes space and material.


The Formula


Minimum QR code width = Scan distance / 10


This rule of thumb works for most scenarios with modern smartphone cameras. For more precision:


module-size/" class="glossary-term-link" data-term="Module size" data-definition="Physical dimension of one module (min 0.33mm)." data-category="QR Code Structure">Module size (mm) = Scan distance (mm) / (10 x Modules per side)


Quick Reference Table






Scan Distance
Min Size (V2, 25 mod)
Min Size (V5, 37 mod)
Min Size (V10, 57 mod)






10 cm
1.0 cm
1.5 cm
2.3 cm




30 cm
3.0 cm
3.0 cm
3.0 cm




50 cm
5.0 cm
5.0 cm
5.0 cm




1 m
10 cm
10 cm
10 cm




3 m
30 cm
30 cm
30 cm




5 m
50 cm
50 cm
50 cm






Note: At close range, higher-version codes need proportionally larger sizes. At distance, the 10:1 rule dominates for all versions.


Factors That Increase Minimum Size


    

  • Low lighting: Cameras need more pixels per module in dim conditions
    • 

  • Curved surfaces: Distortion effectively reduces module size
    • 

  • Low contrast: Reduced contrast requires larger modules for reliable binarisation
    • 

  • Older cameras: Lower resolution cameras need larger modules
    • 

  • Non-standard modules: Rounded or dot-style modules with reduced fill
    • 



Factors That Allow Smaller Sizes


    

  • Close, controlled scanning: Products held in hand (10-20 cm)
    • 

  • High-quality print: Laser-printed on smooth paper
    • 

  • High-contrast: Black on white with strong lighting
    • 

  • Modern cameras: 12+ MP cameras resolve fine modules
    • 



Safety Margin


Always add a 20-30% safety margin to the calculated minimum size. Real-world conditions (angle, motion, lighting variation) reduce effective scanning performance compared to ideal calculations.


Key Takeaways


    

  • Rule of thumb: QR width = scan distance / 10
    • 

  • Higher-version codes need larger physical sizes at close range
    • 

  • Add 20-30% safety margin for real-world conditions
    • 

  • Low light, curved surfaces, and low contrast increase size requirements
    • 

  • Always test at the actual deployment distance
    •