Mr Calcu | Make your QR codes unbreakable—estimate error correction and ensure scan reliability in any condition.

Boost QR code reliability and recoverability with our ECC calculator. Discover how to protect your data even when codes are damaged or distorted.

QR Code Error Correction Estimator

QR Code Version (1-40)

Error Correction Level

Data Capacity (characters)

QR Code ECC Estimator Guidelines

Ready to build a bulletproof QR code? Follow these steps to estimate your ideal ECC level:

Select a QR code version (1–40) to define capacity.
Choose an error correction level: L, M, Q, or H based on recovery needs.
Enter estimated data size to ensure fit within selected parameters.
Use the output to find total and ECC codewords, and calculate recovery percentage.
Balance data size with robustness—Level H offers best protection, but lowest capacity.

QR Code ECC Estimator Description

What is QR Code Error Correction?

QR codes use built-in error correction to ensure readability even when damaged or obscured. This is made possible through Reed-Solomon encoding, which allows the QR scanner to reconstruct missing or corrupted data.

Error Correction Levels

L (Low): Recovers up to 7% of data.
M (Medium): Recovers up to 15% of data.
Q (Quartile): Recovers up to 25% of data.
H (High): Recovers up to 30% of data.

Pro Tip: Choose higher ECC levels for QR codes exposed to wear, smudges, or outdoor conditions. Level H can restore data even if one-third of the QR code is missing!

How It Works: Technical Explanation

Error correction relies on Galois Fields (GF(256)) and the Reed-Solomon algorithm, which adds parity blocks to the original data.

Key Formula:

Recovery % = (Number of ECC codewords / Total codewords) × 100

Each QR code version defines a fixed number of total codewords. The number of error correction codewords depends on the selected error correction level.

Example:

Version 4 QR code at Level H has 80 codewords total, with 30 for ECC. This results in:

(30 / 80) × 100 = 37.5% recovery

Use Cases

Case Study 1: Outdoor Tool Labeling

Company uses Level H for QR codes on rugged tools.
Scanners read codes even after scratches and mud exposure.
Version 8 used for moderate data with high robustness.

Case Study 2: Concert Tickets

Level Q selected for a balance of capacity and durability.
Tickets scanned despite smudging from rain.
Version 10 used to embed seat and access info.

Common Edge Cases

1. Sticker Obstruction

QR partially covered with a label? If damage is < 30%, Level H may recover it.

2. Low-Resolution Printing

High-density QR codes printed at 72 DPI often fail. Even ECC can’t help if modules blur together.

3. UV Fading

Overexposure to sunlight reduces contrast. Level Q may buy time, but contrast loss can still cause failure.

4. Reflections on Glass

Glare distorts QR code readability. Level H helps when distortion is scattered but not when entire sections are obscured.

5. Micro QR Use

Micro QR codes offer limited ECC (L or M). Ideal for static and clean environments only—scratches or smudges quickly cause failure.

Start testing your QR code's resilience now—use the ECC Estimator and make your codes unstoppable.

Example Calculation

Version	Error Correction Level	Total Codewords	ECC Codewords	Estimated Recovery
2	L	44	10	22.7%
4	Q	80	28	35.0%
8	H	156	66	42.3%
10	M	224	50	22.3%
20	H	652	282	43.2%

Frequently Asked Questions

QR code error correction is a mechanism that allows data recovery even when the QR code is damaged or partially obscured.

Higher error correction levels provide greater recovery capacity but reduce data storage capacity.

Not always. Higher error correction levels reduce how much data the QR code can hold. Use Level H for critical data, but for larger payloads, consider Level M or Q.

Each QR code version has a fixed total number of codewords. Based on the error correction level, a predefined portion is allocated to error correction using Reed-Solomon encoding.

You’ll need to increase the QR code version or reduce the ECC level to fit the data. Use the calculator to test combinations.

No. ECC performs best when errors are evenly distributed. Large continuous damage may exceed recoverable limits, even within theoretical thresholds.

Choose based on your environment: Level H for high-damage risk, Level Q for balance, and Level M or L for large data in clean, controlled conditions.