Visually test the limits of error correction levels
How to use: Enter text or upload a QR code image.
The tool generates a QR code at each error correction level (L/M/Q/H) and hides modules just below and above the tolerance limit to test whether the code is still readable.
For example, at Level M (recoverable up to 15%), it generates three QR codes hiding 14%, 15%, and 16% so you can check the boundary.
Text Input
Upload QR Code Image
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Drag & drop an image / click
Generating...
About QR Code Error Correction Limit Testing
QR Code EC Tester is a free online tool that lets you visually check the limits of the error correction feature of QR codes. When embedding a logo into a QR code or creating a design QR code, you can verify in advance how much you can hide while keeping the code readable.
Comparison of Error Correction Levels
Level
Recovery Capacity
Use Case
L
About 7%
When maximizing data capacity. Use in clean environments.
M
About 15%
Standard use. The most commonly used level for general QR code generation.
Q
About 25%
Somewhat harsh environments. Also supports embedding small logos.
H
About 30%
Logo embedding and harsh printing environments. Ideal for design QR codes.
Use Cases
Ideal for designers who want to place a logo-embedded QR code on business cards or posters, quality control staff who want to verify QR code robustness, and engineers or students who want to understand how error correction works. The center block mask simulates logo placement, while the random scatter mask simulates real-world soiling or damage. To learn how error correction works, see the article "How QR Code Error Correction Works".
Related Tools
Combine these QR tools to go from generation to analysis to limit testing in one workflow.
QR Code Generator — Create a QR code with a chosen error correction level and size.
QR Code Analyzer — Analyze error correction level, version, and mask pattern.
Wi-Fi QR Generator — Build a Wi-Fi connection QR code from an SSID and password.
How should I choose the error correction level for a QR code?
Choose based on your use case. Level L (7% recovery) is for maximizing data capacity, Level M (15% recovery) is for standard use, Level Q (25% recovery) is for somewhat harsh environments, and Level H (30% recovery) is suited for embedding logos and harsh printing environments.
Can a QR code still be read if I add a logo to it?
Yes, you can place a logo in the center of a QR code by using the error correction feature. At Level H, the code can be recovered even if up to about 30% of the modules are damaged, so a design that covers the center with a logo is possible. This tool lets you check the actual limits.