Logo Size Limit

Why It Matters

For developers and product teams, Logo Size Limit directly impacts user experience and system reliability. If a logo exceeds the defined size, the QR code may become unreadable or fail to scan in low-quality environments such as printed materials or mobile device screens. This can lead to failed redirects, lost engagement, or customer frustration.

From a security perspective, maintaining scannability is essential for fraud prevention. If a QR code becomes corrupted or unreadable due to oversized logos, attackers might exploit this to redirect users to malicious links or create confusion in legitimate campaigns. Additionally, in operational workflows involving large-scale QR code deployment, exceeding the limit can cause batch processing failures or inconsistent scanning performance.

How It Works

The Logo Size Limit operates within PixQR’s internal rendering pipeline, where logo dimensions are validated against predefined thresholds before QR code generation. The system enforces this limit to ensure the code’s structural integrity remains intact. The mechanism includes:

• Pixel-based validation for logo width and height, with maximum dimensions set to 10% of the QR code’s total module count.
• Aspect ratio preservation during logo embedding to prevent distortion that could impact scannability.
• Automatic scaling of logos that exceed the defined size, maintaining the original image’s visual quality as much as possible.
• Integration with error correction levels (L, M, Q, H) to ensure that even with logo insertion, the code remains within scannability thresholds.
• Support for multiple logo formats including PNG, JPEG, and SVG, with internal conversion and optimization to fit within the size constraints.

Quick Reference

Basic Example

PixQR Example QR

This QR links directly to this glossary page, so printed notes, onboarding docs, and support material can bring scanners back to the current reference.

/glossary/qr-code-error-correction/qr-code-error-correction-logo-size-limit

This basic example demonstrates how a developer might define a logo within a PixQR code generation request, ensuring it complies with the Logo Size Limit.

{
  "logo": {
    "url": "https://example.com/logo.png",
    "width": 50,
    "height": 50
  },
  "error_correction": "M"
}

The width and height values are set to 50 pixels, well within the 10% threshold. The error correction level is set to "M" to provide a balance between scannability and code density.

Production Example

In a production environment, developers must validate logo dimensions and handle potential errors gracefully. This example includes validation logic to ensure compliance with the Logo Size Limit before generating a QR code.

function validateLogoSize(width, height, qrSize) {
  const maxSize = Math.floor(qrSize * 0.1);
  if (width > maxSize || height > maxSize) {
    throw new Error("Logo exceeds maximum size limit");
  }
}

const logoWidth = 80;
const logoHeight = 80;
const qrModuleCount = 256;

validateLogoSize(logoWidth, logoHeight, qrModuleCount);

const payload = {
  "logo": {
    "url": "https://example.com/brand.png",
    "width": logoWidth,
    "height": logoHeight
  },
  "error_correction": "Q"
};

This version is more suitable for production because it includes validation logic to prevent runtime errors and ensures that all inputs meet the system’s constraints before QR code generation.

Common Mistakes

• Assuming logos can be any size without affecting scannability. This leads to failed scans in real-world applications.
• Ignoring the error correction level when embedding logos. A lower correction level may not compensate for oversized logos.
• Not validating logo dimensions before QR code generation. This causes runtime errors and inconsistent output.
• Using logos with high resolution without scaling. High-resolution logos may exceed the limit even if visually small.
• Overlooking format compatibility. Some formats may not be supported or may not scale well within the limit.

Security And Production Notes

• Always validate logo dimensions to prevent system-level errors or degraded performance.
• Use error correction levels that accommodate the logo size to ensure reliability.
• Test QR codes in various environments to confirm scannability after logo insertion.
• Implement auto-scaling to reduce manual intervention and maintain consistent branding.
• Log or monitor violations of the Logo Size Limit to detect potential misuse or system misconfigurations.

Related Concepts

Several developer concepts are closely related to Logo Size Limit:

• QR Code Error Correction Levels – Define how much damage a QR code can sustain while remaining scannable. Higher levels allow more flexibility for embedded elements.
• Module Count – The total number of squares in a QR code grid. Logo size is calculated relative to this.
• Scanning Reliability – The ability of a QR code to be read accurately under various conditions, including physical damage or low-quality printing.
• Dynamic Redirects – The process of redirecting users to a URL upon scanning. Logo insertion must not interfere with this process.
• Brand Safe Design – Ensuring logos are embedded in a way that preserves brand identity without compromising functionality.

Further Reading

• MDN Web Docs
• WHATWG HTML Standard
• QR Code Error Correction Guide
• ISO/IEC 18004:2015 QR Code Standard
• PixQR API Documentation