QR Code Scanner
Upload an image to detect QR code content (processed locally)
Free online QR code scanner. Upload or drag an image to instantly decode QR codes, with camera support on mobile. Copy results or open links directly; all processing is local and private.
Related
What is a QR Code?
A QR Code (Quick Response Code) is a two-dimensional barcode made up of black and white square modules arranged in a matrix, invented by the Japanese company Denso Wave in 1994. Compared to traditional one-dimensional barcodes, QR codes can store more information in the same area and include error correction, allowing them to be decoded even when partially damaged.
**QR Code Structure:** The three large square patterns at the corners are Position Detection Patterns, used to quickly locate the QR code's position and orientation; Timing Patterns help determine module coordinates; Alignment Patterns assist in correcting perspective distortion; Format Information stores the error correction level and mask pattern; the Data Area contains the actual encoded content.
**Why scan QR codes on a computer?** In daily work, you often receive screenshots, documents, or web pages containing QR codes on your computer, and reaching for your phone to scan them is inconvenient. Using this tool, you can upload an image directly on your computer to decode it, eliminating the need to grab your phone, which is especially useful in office settings.
**QR codes vs. barcodes:** One-dimensional barcodes (such as Code 128, EAN-13) can only encode a small amount of data horizontally and are mainly used for retail products. QR codes store information both horizontally and vertically, offering much larger capacity and supporting URLs, text, contact information, Wi-Fi configuration, and more, making them far more widely used.
Use Cases
- Quickly extract links or text from QR code screenshots or images received on your computer
- Decode QR codes directly on your computer when your phone is not nearby or inconvenient to use
- Decode and view the actual content of QR codes from posters, documents, or web pages
- On mobile devices, directly use the camera to scan QR codes in real time
How to Use
- Click the upload area to select a QR code image, or drag and drop the image directly onto the upload area
- The tool automatically performs multi-scale scanning to recognize and decode the QR code content
- View the recognition result, click the copy button to copy the content, or open URLs directly
Features
- Image upload decoding: click to select or drag and drop an image to automatically recognize QR code content
- Multi-format support: compatible with JPG, PNG, WEBP, GIF, BMP and other common image formats
- Camera capture: on mobile devices, directly use the camera to take a photo and scan
- Multi-scale scanning: automatically tries multiple zoom levels to improve recognition of blurry or distant QR codes
- One-click copy: copy decoded results to clipboard; URLs can be opened directly with a click
- Local processing: all recognition happens in the browser; images are never uploaded, keeping your data private
FAQ
How do I scan a QR code from an image?
Click the upload area to select an image containing a QR code, or drag and drop the image directly onto the upload area for automatic recognition and decoding. Supports common formats such as JPG, PNG, WEBP, GIF, and BMP. Results are displayed directly on the page and can be copied with one click.
How do I scan a QR code on a computer without a webcam?
Simply upload the screenshot, photo, or downloaded image containing the QR code to this tool. No camera or scanning software installation required. Ideal for situations when your phone is not nearby and you need to quickly extract content from a QR code received on your computer.
Can I use my phone camera to scan directly?
Yes. On mobile devices, tapping the upload button lets you take a photo with your camera. Point it at the QR code to scan directly, no need to save the photo first before uploading.
Can a blurry QR code or one with a logo still be recognized?
QR codes have four error correction levels (L=7%, M=15%, Q=25%, H=30%). Slight blurriness, a center logo, or partial damage can usually still be decoded. This tool uses a multi-scale scanning algorithm that automatically tries different zoom levels to improve recognition success. However, if the three corner position detection patterns are severely missing or blurred, recognition may fail.
Will my uploaded QR code images be saved to a server?
No. All QR code recognition is performed locally in your browser using the jsQR library. Images are never uploaded to any server and are discarded after processing. You can safely use it even for QR codes containing passwords, Wi-Fi credentials, or payment information.
Can I open a recognized URL directly?
Yes. When the result is an http or https link, an "Open Link" button appears in the result area. Click it to open the URL in a new tab without manually copying and pasting it into your browser.
Glossary
- QR Code
- Short for Quick Response Code, a matrix two-dimensional barcode standard invented by Denso Wave in 1994. ISO/IEC 18004 is its international standard. There are 40 versions ranging from Version 1 (21×21 modules) to Version 40 (177×177 modules); higher versions offer greater data capacity.
- Error Correction Level (ECC)
- QR code error correction has four levels: L (~7% recovery), M (~15%), Q (~25%), and H (~30%). Higher error correction tolerates more damage but reduces data capacity. QR codes with a center logo typically use level Q or H.
- jsQR
- A pure JavaScript QR code decoding library. This tool uses jsQR to perform QR code recognition locally in the browser without uploading images to any server. It supports multi-scale scanning to improve recognition success rates.jsQR GitHub
- vCard
- A standard electronic business card format with the .vcf file extension. QR codes can encode vCard contact information; after scanning, the contact can be added directly to your phone's address book, including fields such as name, phone, email, company, and address.
Content Types Encodable in QR Codes
| Content Type | Example | Typical Use |
|---|---|---|
| URL | https://example.com | Scan to open a link |
| Plain Text | Hello World | Extract text content |
| Contact (vCard) | BEGIN:VCARD ... | Scan to add a contact |
| Wi-Fi | WIFI:T:WPA;S:ssid;P:pass;; | Scan to connect to Wi-Fi |
mailto:hi@example.com | Scan to open email client | |
| SMS | smsto:10086:hello | Pre-fill an SMS message |
| Geo Location | geo:39.9,116.4 | Scan to open map coordinates |
| Phone Number | tel:+8610086 | Scan to dial a number |
QR Code Error Correction Levels
| Level | Recovery Capacity | Typical Use |
|---|---|---|
L | ~7% | Maximum data capacity, unobstructed scenes |
M | ~15% | Industry standard, general commercial use |
Q | ~25% | Moderate obstruction, small logo in center |
H | ~30% | High tolerance, larger logo in center |
Authoritative References
- ReferenceQR Code Official Standard ISO/IEC 18004
- ReferenceWikipedia - QR code
- ReferencejsQR - JavaScript QR Code Decoding Library
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