What image formats can I upload?

Any format your browser can decode: PNG, JPG, GIF, WebP and BMP all work. Transparent backgrounds and slight rotations are fine; very blurry or low-contrast scans may fail to decode.

Can it read QR codes from a screenshot?

Yes. Screenshots work as long as the QR code itself is reasonably clear. If the code is small in the image, crop closer to the code for more reliable decoding.

What kinds of QR content does it decode?

URLs, plain text, Wi-Fi credentials, vCards, phone numbers, SMS prefills, email prefills and geolocation links are all shown as the raw decoded text. Follow the link or copy the text. Nothing is opened automatically.

Why does decoding fail for some images?

Very low resolution, strong blur, extreme perspective skew, or insufficient contrast can prevent decoding. Re-scan with better lighting or a higher-resolution camera and try again.

Is my image uploaded to a server?

No. Decoding runs entirely in your browser using the jsQR library loaded from a public CDN. The image and the decoded text never leave your device.

मुफ़्त QR कोड रीडर ऑनलाइन

QR कोड की सामग्री को तुरंत डीकोड करने के लिए एक छवि आयात करें या ड्रैग-ड्रॉप करें।

स्थानीय रूप से डिकोड किया गया · आपकी छवियाँ कभी भेजी नहीं जातीं

यहाँ QR कोड छवि छोड़ें या अपलोड करने के लिए क्लिक करें

PNG, JPG, GIF, BMP, WebP समर्थित

डिकोड की गई सामग्री

इस QR कोड रीडर का उपयोग कैसे करें

अपलोड क्षेत्र पर क्लिक करें या QR कोड वाली छवि ड्रैग-एंड-ड्रॉप करें।
टूल तुरंत QR कोड डिकोड करता है और इसकी सामग्री प्रदर्शित करता है।
डिकोड किया गया टेक्स्ट कॉपी करने के लिए कॉपी पर क्लिक करें, या URL होने पर लिंक खोलें।

QR कोड में क्या हो सकता है?

URL · वेबसाइटों, ऐप स्टोर या सामाजिक प्रोफ़ाइल के लिंक।
सादा टेक्स्ट · कोई भी संदेश या नोट।
WiFi प्रमाणपत्र · स्वचालित कनेक्शन के लिए SSID, पासवर्ड और एन्क्रिप्शन प्रकार।
vCards · संपर्क जानकारी (नाम, फ़ोन, ईमेल, संगठन)।
ईमेल/SMS · पहले से भरे ईमेल पते या फ़ोन नंबर।

अक्सर पूछे जाने वाले प्रश्न

कौन से छवि प्रारूप समर्थित हैं?

PNG, JPEG, GIF, BMP और WebP। कोई भी सामान्य छवि प्रारूप जो आपका ब्राउज़र प्रदर्शित कर सकता है।

क्या मेरी छवि सर्वर पर भेजी जाती है?

नहीं। QR कोड पूरी तरह आपके ब्राउज़र में JavaScript में डिकोड होता है। आपकी छवि कभी आपके डिवाइस से नहीं जाती।

क्या यह स्क्रीनशॉट से QR कोड पढ़ सकता है?

हाँ! स्क्रीनशॉट, फ़ोटो और स्कैन किए गए दस्तावेज़ काम करते हैं। QR कोड बस स्पष्ट और बहुत धुंधला नहीं होना चाहिए।

A 1994 invention at Denso Wave, and a Go board

The QR code was invented in 1994 by Masahiro Hara, an engineer in the development department of Denso Corporation (the spin-off subsidiary that became Denso Wave was formally established later), to solve a specific problem in Japanese automotive manufacturing. Toyota's lean manufacturing model, with its emphasis on Kanban tags and high-mix low-volume production, was generating more SKUs than the existing one-dimensional barcodes could handle. A standard linear barcode of the kind printed on supermarket products holds about twenty characters; a single automotive part might need to track an order number, part number, lot, supplier, and process flag, so workers ended up reading about ten barcodes in a row, with a corresponding rate of misreads. Hara was tasked in 1992 with designing a two-dimensional code that could carry the whole tag in one symbol, in any orientation, fast.

The famous origin story has Hara realising the encoding scheme during a lunchtime game of Go, the ancient board game in which black and white stones are arranged on a 19×19 grid. The black-and-white modules of a matrix barcode are essentially Go stones on a square lattice, and Hara recognised that the dense two-dimensional pattern could carry far more information than a one-dimensional barcode of the same physical area. The other piece of the puzzle was orientation: how does a scanner know where the code starts, ends, and which way is up, when the code is photographed at a slant or upside down? Hara's answer is the three concentric-square finder patterns in three corners of every QR code.

To pick a pattern that wouldn't collide with normal print, Hara's team surveyed thousands of magazines, newspapers, and printed materials and tabulated the run-length frequencies of black and white regions. They found that the ratio of stripe widths 1:1:3:1:1 (a thin black, thin white, thick black, thin white, thin black) almost never appeared in ordinary print. That ratio is what scanners look for. When a camera spots three regions in an image whose stripe widths match 1:1:3:1:1 along both axes, it can confidently call them the three corners of a QR symbol and rectify the perspective from there. The ratio held up well enough that QR codes can be decoded on curved surfaces, at angles up to about thirty degrees, and through partial occlusion.

The open-licensing decision

Denso Wave's other decisive contribution was strategic rather than technical. The company holds patents on the QR code (and continues to register patents on derivatives like the iQR and SQRC), but it has explicitly waived royalty rights for use of QR codes that conform to the public JIS and ISO standards. Denso Wave's public position, restated on its qrcode.com FAQ and patent pages, is that no licence is needed, no contract is required, and no fee is owed for commercial use of the QR code so long as the symbol follows the ISO/IEC 18004 specification. The trademark on the term "QR Code" is registered, but the underlying matrix barcode is free.

This was not the obvious move in 1994. Symbol Technologies, which then owned the PDF417 patent, was charging royalties; Aztec and Datamatrix had similarly encumbered histories early on. Denso Wave's choice to give the format away meant that anyone (printer manufacturers, mobile phone makers, payment networks, restaurant chains, contact-tracing app developers) could integrate QR codes with no legal friction. That decision is the single biggest reason QR codes won the 2D-barcode race in consumer applications.

Reed-Solomon error correction: why a smudged QR still works

The reason a QR code keeps working when it's partially smudged, torn, or covered with a small logo is Reed-Solomon error correction, a forty-year-old coding-theory technique. Reed-Solomon codes were introduced in a five-page paper, "Polynomial Codes over Certain Finite Fields," by Irving S. Reed and Gustave Solomon, then staff members at MIT Lincoln Laboratory. The paper was completed as an internal Lincoln Lab report in December 1958 and published in slightly modified form in the Journal of the Society for Industrial and Applied Mathematics, vol. 8, pp. 300-304, in 1960. Reed and Solomon were originally working on the SAGE air-defence system, which needed to keep radar signals coherent over noisy wartime communication links. Their insight was that a sequence of data could be treated as the coefficients of a polynomial over a finite field, evaluated at a set of points; the redundancy in the over-evaluation lets a receiver recover the polynomial even when some of the evaluations are wrong. That same mathematics underlies CDs, DVDs, deep-space probe transmissions, broadcast television, and (since 1994) every QR code in the world.

QR codes offer four user-selectable error-correction levels, each a different trade between data capacity and robustness:

Level L (low): ~7% codeword recovery
Level M (medium): ~15%, the practical default
Level Q (quartile): ~25%
Level H (high): ~30%, high enough that a Level H QR can keep working with a surprisingly large logo pasted across its face

The cost of higher correction is reduced capacity: the same physical version of a QR code holds much less payload at Level H than at Level L because more of the modules are taken up by parity bits.

Capacity at version 40: the upper bound

QR codes come in forty versions. Version 1 is 21×21 modules. Each successive version adds 4 modules per side, so version 2 is 25×25, version 3 is 29×29, up to version 40 at 177×177 modules. The maximum payloads at version 40 with the lowest error correction (L):

7,089 numeric characters (digits)
4,296 alphanumeric characters (digits, uppercase letters, space, a few punctuation marks)
2,953 bytes of arbitrary binary data (which encompasses UTF-8 text)
1,817 kanji characters in Shift JIS encoding

These maximums fall sharply with higher correction: at Level H the same version 40 symbol holds only 3,057 digits, 1,852 alphanumeric characters, 1,273 bytes, or 784 kanji. In practice, QR codes with more than a few hundred bytes are rare; by the time you reach version 20 or so, the modules become too small to scan reliably from a phone at arm's length without a high-resolution camera.

Datamatrix, Aztec, PDF417: the QR alternatives you'll see in the wild

Datamatrix (late 1980s, ISO/IEC 16022) is a square or rectangular matrix barcode optimised for very small marks, with a single L-shaped finder pattern. It dominates small-part marking (circuit boards, surgical instruments, pharmaceutical unit doses) and the EU's Falsified Medicines Directive serialisation, which since 2019 requires every prescription medicine box to carry a Datamatrix.
Aztec (1995, ISO/IEC 24778) gets its name from the bullseye finder pattern at its centre, which evokes a stepped Aztec pyramid viewed from above. Its distinguishing feature is that it requires no quiet zone (no blank border around the symbol), which lets it fit in cramped spaces such as the corner of a paper boarding pass. Standard for airline e-tickets and many train and transit systems in Europe.
PDF417 (Symbol Technologies 1991, ISO/IEC 15438) is technically a "stacked linear" code rather than a true matrix code: multiple rows of linear barcodes stacked one above another. The densest of the four for plain ASCII text, it can carry over a kilobyte of data, used on the back of US driver's licences (encoding the full magnetic-stripe data plus more) and on FedEx and other shipping labels.

Among these four, QR codes won the consumer market for three reasons: omnidirectional scanning thanks to the three corner finders, the open licensing, and the deep integration with the Japanese mobile-phone industry in the late 1990s, which gave them a critical mass of installed scanners before any competitor.

ISO standardisation timeline

QR codes were first published as a Japanese Industrial Standard (JIS X 0510) in January 1999 and as an international standard, ISO/IEC 18004, in June 2000. ISO/IEC 18004:2006 (September 2006) replaced it; this defined "QR Code 2005," a slight extension of Model 2 with additional alignment patterns. ISO/IEC 18004:2015 (February 2015) renamed the symbol simply "QR Code" (dropping the year suffix), folded in clarifications, and corrected minor errors. The current edition is ISO/IEC 18004:2024, the fourth edition, published in August 2024. The standard, like all ISO publications, is sold as a paid PDF; several open-source implementations (notably ZXing) have served as living references for the spec.

The Denso Wave variants: Micro QR, iQR, SQRC, rMQR

Hara's original 1994 specification is now called Model 1. Model 2, defined in 1997, is the version most people now mean when they say "QR code"; it extends to version 40 and is the basis for the modern ISO standard. Micro QR Code uses only one finder pattern and a smaller quiet zone, fitting in tighter spaces. iQR Code, introduced by Denso Wave in 2011, has up to 80% more capacity than Model 2; can be square or rectangular, reaching 422×422 modules and 40,000 digits. SQRC (Secure QR Code) carries two layers: a public layer readable by any QR scanner, and a private encrypted layer requiring a special reader and key. rMQR (Rectangular Micro QR Code) was standardised in 2022 as ISO/IEC 23941: a hybrid of Micro QR and iQR, much wider than tall, fitting narrow strips like the side of a label or the edge of a printed circuit board.

The post-COVID surge and China's QR-payment culture

QR-code adoption in the West was sluggish for most of the 2010s. Then COVID-19 arrived. With the WHO declaring the pandemic on 11 March 2020, restaurants, transport hubs, and public buildings everywhere needed contactless ways to share menus, log visitors, and process payments, and the QR code was the only mature, hardware-free contactless surface available. By mid-2020, QR-code menus were near-universal in US and European restaurants. QR-payment transaction volume in Singapore reportedly grew about 272% year-on-year through 2021. Many of those uses (especially the menus) have receded since the acute phase, but the cultural barrier to scanning a QR in public was permanently broken.

The other engine of QR adoption (chronologically the earlier one) is China's mobile-payment ecosystem. Alipay introduced QR payments in 2011; Tencent's WeChat Pay followed in 2014 and supercharged adoption with the Spring Festival "red envelope" feature, expanding from 30 million to 100 million users within a month of launch. By 2016, more than $1.65 trillion in transactions flowed through QR-code payments in China. Today, Alipay holds roughly 53% of the Chinese mobile-payment market and WeChat Pay roughly 42%, together about 90%. More than 90% of mobile payments in China are made via QR codes, and roughly 70% of the population uses them regularly.

When the West got native QR scanning

The other major catalyst for Western adoption was native camera support. Apple shipped iOS 11 in September 2017, and that version's Camera app silently recognised QR codes by default, the first time any iPhone could read a QR without installing a third-party app. Apple didn't even mention the feature at WWDC 2017; reviewers discovered it after the public release. The change reached more than 700 million iPhones in the first year. Google followed: Google Lens added QR support in May 2018 and began rolling out to ten Android manufacturers' camera apps; Android 9, released the same year, made native QR scanning standard on the platform. Within roughly a year, the era of dedicated "QR scanner" apps effectively ended.

Quishing: the rise of QR phishing

The same low-friction scanning that made QR codes useful in the pandemic also made them attractive to phishing-attack designers. Quishing (phishing via QR code) uses a QR image embedded in an email or printed flyer to deliver a malicious URL. Because the URL is hidden inside the code, traditional email security gateways that scan link text can't inspect it; because the user is typically prompted to scan with a personal mobile device, the attack moves from the corporate network (with its protections) to a phone (often without).

The scale grew quickly. From 2021 to 2023, QR-code scans rose 433%. The fraction of phishing emails using a QR payload rose from about 0.8% in 2021 to about 12.4% in 2023, and stabilised at roughly 10.8% in 2024. By 2023, QR codes appeared in 22% of all phishing attacks. Roughly 27% of quishing emails impersonate multi-factor authentication notices; about 90% target login credentials. C-suite executives are 42 times more likely than rank-and-file employees to receive a quishing attempt. The defensive answer security teams have settled on: don't auto-open QR payloads. Decode them, look at the URL in plain text, and decide. That's exactly what an image-based QR reader (like this one) lets a careful user do.

URI schemes you'll commonly see decoded

A QR code is just a wrapper around a string of bytes; the meaning of those bytes is dictated by convention. A small number of conventions cover almost everything seen in the wild:

http: / https: URLs, by far the most common.
mailto: URIs (with optional ?subject= and ?body= query parameters) populate an email draft.
tel: URIs trigger a phone call.
sms: URIs (and the older SMSTO: form, popularised by NTT DoCoMo) prefill a text message.
geo: URIs open a map at a specific latitude and longitude.
WIFI: a Denso-Wave-defined informal scheme of the form WIFI:S:<SSID>;T:<WPA|WEP|nopass>;P:<password>;H:<true|false>;; that lets a phone join a network with one tap. The workhorse of guest-WiFi posters.
MECARD: (NTT DoCoMo), a compact contact format.
vCard (RFC 6350), the verbose international standard for contacts, widely supported despite its size.

This reader shows the decoded payload as plain text. Following the link or copying the text is your decision; nothing is opened automatically.

How browser-based decoding works under the hood

Two open-source libraries dominate browser-side QR decoding. jsQR, written by Daniel Beaver under the GitHub handle "cozmo," is a pure-TypeScript port that takes raw ImageData (the pixel array from a canvas, video frame, or uploaded image) and returns the decoded text. It has no dependencies, no platform-specific code, and is small enough to ship from a CDN as a single script tag. This tool uses jsQR. The other major option is the JavaScript port of ZXing ("Zebra Crossing"), an originally Java barcode library that supports many more 2D and 1D formats than just QR, published as @zxing/library and @zxing/browser on npm.

A third path is the platform-native BarcodeDetector API, part of the W3C Shape Detection API, which exposes a browser-built-in barcode reader to JavaScript. BarcodeDetector shipped enabled-by-default in Chrome 83 in May 2020 (Microsoft Edge picked it up at the same time). However, the API is platform-dependent: it relies on operating-system-level barcode detection and is fully supported on macOS, Android, and Chrome on Android; Windows and Linux Chrome don't implement it. Firefox and Safari haven't shipped it. Most production browser QR scanners use jsQR or zxing-js as a fallback, calling BarcodeDetector when available and the JavaScript decoder otherwise.