Erase Parts of a QR Code? Here’s Why It STILL Might Work | QR Code Error Correction Explained + Live Demo

Easy guide to QR codes – what they are, how they work, main parts, scanning tips, safety, and creating them for free. Quick answers in a simple FAQ.
SDE Dev



You must have seen QR codes everywhere — on your phone, products, tickets, and more. But did you know, if you erase or cover some parts of a QR code, will it still work? Let’s find out in a simple way! 

What is a QR Code? 

A QR code is like a small picture made of many tiny black and white squares (called modules). It stores useful info like a website link or a message.

Your phone camera scans this pattern and tells you what the QR code says. Easy, right?

Important Parts of a QR Code 

Not all parts of the QR code are the same! Some parts are very important:

  • Finder patterns: The three big squares on the corners. They help your phone find the QR code and understand its position.

  • Timing patterns: Lines of black and white squares near the finders. They help your phone count the rows and columns.

  • Quiet zone: The empty space around the QR code. It lets your phone know where the QR code starts and ends.

  • Data area: The rest of the small squares that carry the actual information.

The Magic of Error Correction

QR codes are smart! They can fix mistakes by themselves if some parts get dirty or erased. This is called error correction.

There are 4 levels of error correction:

  • L: Fix about 7% damage

  • M: Fix about 15% damage

  • Q: Fix about 25% damage

  • H: Fix about 30% damage

So if you cover a small part of the QR code with a sticker or a logo, it usually still works! Cool, right? 

What If You Erase Parts of the QR Code? 

  • Erase finder patterns or quiet zone → QR code will NOT work.

  • Erase timing patterns → It might NOT work.

  • Erase some data squares but damage is small (within error correction) → QR code STILL works!

  • Erase too many data squares → QR code WILL fail.

Try It Yourself!

I made a simple webpage where you can see a real QR code. You can click on any small square inside the QR code to erase it (make it white) and check if it still scans!



  • If erased parts are small → It will say Scan Success 

  • If erased parts are too many or important → It will say Scan Failed 

Download the interactive QR code page here:

👉 https://drive.google.com/file/d/1J4ip_rFPrOlm_sP8xS0Hxc3Kz8lJjXRc/view?usp=drive_link 

How to Run the QR Code Page on Your Computer 💻

  1. Download the index.html file from the link above.

  2. Open the file by double-clicking it — it will open in your web browser.

  3. You will see a QR code on the screen.

  4. Click on any small square inside the QR code (except the empty border) to erase or restore it.

  5. See if the code still works — the message below will tell you!

  6. Click Reset QR Code to start fresh.

  7. You can also scan the QR code with your phone’s camera to test.

1. What is a QR code?
A QR code is a square barcode made of black and white boxes. It can store links, text, or other info that your phone can scan.

2. Will a QR code work if damaged?
Yes, most QR codes work even if up to 30% is damaged, but if the big corner squares are gone, it may not scan.

3. How much can a QR code store?
It can store thousands of numbers, letters, or even pictures, depending on size and settings.