What error correction level in QR code should I choose?

The optimal error correction level for your QR code depends on your specific use case and requirements. QR codes offer four error correction levels, each providing a different degree of fault tolerance:

1. Level L (Low) – recovers up to 7% of lost data

2. Level M (Medium) – recovers up to 15% of lost data

3. Level Q (Quartile) – recovers up to 25% of lost data

4. Level H (High) – recovers up to 30% of lost data

Here are some factors to consider when choosing an error correction level:

1. Data density: Higher error correction levels increase the density of the QR code, making it larger and more complex. If you have size constraints, you may need to choose a lower error correction level.

2. Durability and damage risk: If the QR code is likely to be exposed to wear, damage, or distortion (e.g., outdoor usage, printing on rough surfaces), a higher error correction level will provide better resilience.

3. Scanning environment and devices: Higher error correction levels can make the QR code harder to read for some devices or in poor lighting conditions. You'll need to balance error correction with scanability.

4. Importance of the data: If the data in the QR code is critical and losing it would cause significant problems, a higher error correction level is recommended.

In general, Level M is a good starting point for most applications, as it provides a reasonable balance between error correction and scanability. However, you should test your QR code in its intended environment and with the devices your audience is likely to use to ensure the best results.