Free QR Code Generator Online
Create QR codes for URLs, text, WiFi passwords, or contact cards. Download as PNG or SVG · no sign up needed.
What Is a QR Code?
A QR (Quick Response) code is a 2D matrix barcode that stores data such as URLs, text, Wi-Fi credentials, or contact information. Point a phone camera at one and the device decodes the modules and acts on the payload. QR codes turn up on business cards, restaurant menus, product packaging, event tickets, marketing posters, payment terminals, and the back of countless modern objects.
A Short History of the QR Code
QR codes were invented in 1994 by Masahiro Hara, an engineer at Denso Corporation (later spun off as Denso Wave), to solve a Japanese-automotive-supply-chain problem. Toyota's lean manufacturing model generated more SKUs per workpiece than the roughly 20 characters a one-dimensional barcode could carry, so workers were scanning ten codes in a row per part. Hara's brief was to design a 2D code that carried the whole tag in one symbol, in any orientation, fast. He has said in interviews that the matrix-grid layout came partly from the black-and-white stones of a Go board on his lunch break. The harder problem was position detection: how does a scanner know where the code starts and which way is up when it 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 marker that would not collide with normal print, his team tabulated the run-length frequencies of stripes in thousands of magazines and newspapers and found that the ratio 1:1:3:1:1, thin black, thin white, thick black, thin white, thin black, almost never appears in ordinary printing. That ratio is what scanners search for. Denso Wave's other decisive contribution was strategic: the company holds patents on the QR code but explicitly waived royalty rights for any use that conforms to the public ISO/IEC 18004 specification, first published in June 2000 with major revisions in 2006 (defining «QR Code 2005»), 2015 (renaming it simply «QR Code»), and the current fourth edition of August 2024. The «QR Code» trademark is enforced; the underlying matrix barcode is free. That 1994 decision is the single biggest reason QR codes won the consumer-2D-barcode race against PDF417, Aztec, and Datamatrix. Mass-market adoption arrived with native phone-camera detection: iOS 11 in September 2017 and Google Lens in May 2018. Today every modern phone reads QR codes from its default camera app without a separate scanner.
The Anatomy of a QR Code
- Finder patterns. Three concentric squares in the top-left, top-right, and bottom-left corners. The scanner finds them first because of the unmistakable 1:1:3:1:1 dark-light-dark-light-dark module run, a ratio that Hara's team confirmed almost never appears in normal printed material. The fourth corner of any version-2-or-larger code carries a smaller alignment pattern for perspective correction when the symbol is photographed at an angle.
- Versions and module count. QR codes come in 40 versions. Version 1 is 21x21 modules; every subsequent version adds 4 modules per side, so version 40 is 177x177. The version number is determined automatically by the encoder from the payload size and the chosen error-correction level. Production QR codes typically sit in the version 4 to version 10 range (33x33 to 57x57 modules) because anything denser becomes hard to scan from a phone at arm's length.
- Encoding modes. QR codes are mode-aware: the data-stream header tells the decoder which character set is in use, and a single symbol can mix modes. Numeric mode packs three digits into ten bits (about 3.33 bits per digit). Alphanumeric mode packs two characters into eleven bits, restricted to uppercase A-Z, digits, space, and the symbols
$ % * + - . / :. Byte mode uses 8 bits per byte and handles mixed-case URLs, UTF-8 text, and binary. Kanji mode uses 13 bits per character for Shift JIS Japanese. Choosing the right mode is what separates a tight 21x21 version-1 code from an unscannable mess of black squares. - Error correction. QR codes use Reed-Solomon error correction, the same coding-theory technique that protects compact discs, deep-space probe transmissions, and DVDs. The original 1960 paper by Irving S. Reed and Gustave Solomon, Polynomial Codes Over Certain Finite Fields in the SIAM Journal on Applied Mathematics, treats a sequence of data as the coefficients of a polynomial over a finite field; the redundancy in the over-evaluation lets a receiver recover the polynomial even when some evaluations are wrong. QR offers four levels: L (about 7%), M (about 15%), Q (about 25%), and H (about 30%). The percentage is the fraction of codewords that can be lost or corrupted and still recovered.
- Maximum payload. At version 40 (177x177 modules) with Level L correction, a QR can carry 7,089 numeric characters, 4,296 alphanumeric, 2,953 bytes (UTF-8 text), or 1,817 kanji. At Level H the same version 40 holds only 3,057 digits, 1,852 alphanumeric, 1,273 bytes, or 784 kanji. In practice almost no real-world QR carries more than a few hundred bytes because handheld scanners begin to struggle with dense version-20-or-larger codes at typical reading distances.
- The quiet zone. Every QR needs a minimum 4-module-wide blank border around the data area. Cropping into the quiet zone breaks scanning even when the data area is intact, because the scanner uses the contrast between quiet zone and finder pattern to lock onto the code. This generator emits the proper quiet zone automatically; if you crop the downloaded image yourself, leave room.
Common Uses for QR Codes
- URLs and marketing. By far the most common payload. The QR encodes a plain
https://...link; a scanner displays the URL before opening it (or should, on reputable apps). Pair the QR with a printed copy of the URL so readers can verify before tapping, especially in physical-world contexts where the printed sheet could have been swapped. - Wi-Fi sharing. The
WIFI:S:<SSID>;T:<WPA|WEP|nopass>;P:<password>;H:<true|false>;;URI scheme lets a phone join a network with one tap. The workhorse of guest-Wi-Fi posters in cafes, Airbnbs, conference venues, and home-office side rooms. Use Level Q or H if the poster will be handled or weathered, because a missing module in a Wi-Fi QR locks out every guest who scans it. - Business cards and contacts. Encode a vCard 3.0 payload (RFC 6350) with name, phone, email, and organisation, and the scanner's phone offers to save the contact directly to the address book. vCards are verbose by QR standards, so a contact card usually sits in the version 6 to version 12 range; Level M is the typical default unless the card will be printed small.
- Mobile payments. Alipay and WeChat Pay popularised QR-based merchant settlement in China starting in 2011 and 2014 respectively; the same pattern now serves Singapore (PayNow), Thailand (PromptPay), India (UPI), and a growing share of Europe. The merchant prints a QR; the customer scans it from a payments app; the app handles authorisation, settlement, and receipt. No NFC hardware or card reader is required at the merchant side.
- Product packaging. A QR on a box can link to manuals, warranty registration, recall information, ingredient lists, or product-authentication systems. Use Level H or Q because shipping cartons scuff, get water-stained, and are sometimes covered with shipping labels. A QR designed for outdoor packaging should also include the URL in printed form as a fallback.
- Event tickets and boarding passes. Encode a unique ticket ID or signed token for fast door-scanning. Most modern airline boarding passes use Aztec rather than QR, but concert tickets, museum admissions, and sports-stadium passes are overwhelmingly QR-based. Level Q or H survives crumpling in a pocket and the brief water exposure of a rainy queue.
Standards and Milestones
- 1994: Denso Wave invents the QR code. Engineer Masahiro Hara designs the symbol over roughly eighteen months at Denso Corporation in Japan, originally for Toyota-supply-chain workpiece tracking. The decisive choice is the three concentric-square finder patterns in the 1:1:3:1:1 ratio, allowing scanners to lock onto a QR at any orientation.
- January 1999: JIS X 0510. The Japanese Industrial Standards committee publishes the first national standard for QR codes, codifying the encoding modes, error-correction structure, and physical-symbol requirements that Denso Wave had been operating internally since 1994.
- June 2000: ISO/IEC 18004:2000. The first international edition, defining the foundational QR Model 1 and Model 2 symbols. Publication at the international level removes any remaining licensing or geographic uncertainty for would-be implementers and clears the path for global adoption.
- September 2006: ISO/IEC 18004:2006. Defines «QR Code 2005», the version that most modern scanners actually implement. Adds clarifications, additional micro-QR variants for cramped industrial uses, and improvements to alignment-pattern placement at higher versions.
- August 2024: ISO/IEC 18004:2024. The current fourth edition. Optimises encoding efficiency, tightens structured-append rules (which let one logical payload split across multiple physical symbols), and aligns terminology with the related rectangular micro-QR specification. Every code emitted by this generator conforms to the 2024 spec.
- 1960: Reed-Solomon codes. Irving S. Reed and Gustave Solomon publish Polynomial Codes Over Certain Finite Fields in the SIAM Journal on Applied Mathematics, volume 8, pages 300-304 (DOI 10.1137/0108018). The same coding-theory technique that protects compact discs, DVDs, and deep-space probe data is what lets a QR code keep working when part of it is smudged, torn, or covered by a logo.
- September 2017 and May 2018: native phone-camera QR detection. Apple ships QR-aware Camera.app in iOS 11 (September 2017); Google rolls out QR detection in Google Lens (May 2018) and pushes it into the default Android camera. Removing the need for a third-party scanner app is the single biggest driver of post-2017 QR adoption in marketing, restaurants, and mobile payments outside East Asia.
- 2021 to 2024: the rise of quishing. QR-code phishing rises from about 0.8% of phishing emails in 2021 to 12.4% in 2023 and stabilises near 10.8% in 2024. C-suite executives are about 42 times more likely than rank-and-file employees to receive a quishing attempt; roughly 27% of quishing emails impersonate multi-factor-authentication notices. Legitimate QR producers respond by avoiding silent tracking redirects and by printing the URL alongside the code so scanners can verify before tapping.
More frequently asked questions
What size should I print my QR code at?
For print, at least 2 cm by 2 cm (about 0.8 inches), which gives roughly a 20:1 ratio of scanning distance to module size at typical phone-camera resolutions. A useful rule of thumb is minimum print size ≈ scanning distance ÷ 10: a QR meant to be scanned from 2 metres away should be at least 20 cm wide; a code on a highway billboard 50 metres away should be at least 5 metres wide.
Why does the same payload sometimes produce different code sizes?
Two reasons. First, the encoder may have upgraded the QR version (more modules per side) because your error-correction level requires more redundancy than fits in the smaller version. Second, the encoder may have changed the mode: an all-digit ID encodes as numeric mode at 3.33 bits per character; the same ID with a letter prefix forces alphanumeric or byte mode, which uses more bits per character and may bump the version up.
Can I embed a logo in the centre without breaking the QR?
Yes, up to about 25-30% of the visible area, if you also raise the error-correction level. Reed-Solomon can recover the modules a logo covers, but only up to the level's recovery percentage. Level H (30%) is the standard choice for logo overlays; Level Q (25%) works for smaller logos. Always scan-test from at least three different phones before committing to print, because the placement of the logo over which specific modules also matters.
What is the difference between static and dynamic QR codes?
A static QR encodes the payload directly: scan it and you get exactly the URL or text that was encoded. A dynamic QR encodes a short tracking URL that redirects through a third-party server, so the destination can be changed without reprinting the code, and every scan can be logged. This generator produces static QRs only: the payload is the payload, no redirects, no tracking. That is slower to update but invisible to phishing scanners and survives the third-party redirect company going out of business.
Are QR codes case-sensitive?
The data is, but the mode determines what fits. Alphanumeric mode only supports uppercase A-Z plus digits, space, and $ % * + - . / :; a URL written in lowercase forces the encoder into byte mode, which uses more bits per character and may bump the QR version up. If you control the destination, using an all-uppercase short path on a domain with no querystring keeps the code as small as possible.
Are my inputs stored or sent anywhere?
No. This generator runs entirely in your browser via the MIT-licensed QRCode.js library. The URL, Wi-Fi password, vCard, and image data are computed and rendered locally; nothing is transmitted to any server, no analytics events log the values, no marketing list captures your inputs. Verifiable in DevTools' Network panel by watching for the absence of any POST after page load. Wi-Fi passwords and vCard phone numbers are exactly the kind of payload server-side generators monetise; this one does not.
Frequently Asked Questions
What's the best size for a QR code?
For print, make the QR code at least 2 cm x 2 cm (about 0.8 inches). For billboards or signs viewed from a distance, scale up proportionally. Rule of thumb: minimum code size equals scanning distance divided by 10.
PNG or SVG: which should I download?
Use PNG for digital use (websites, social media, email). Use SVG for print materials since it's a vector format that scales to any size without losing quality.
Can I customize the colors of the QR code?
Yes. Use the foreground and background color pickers to match your brand. Just keep enough contrast between the two colors, otherwise scanners won't reliably read the code.
Do QR codes expire?
No. QR codes generated here are static: the data is encoded directly in the pattern. They keep working forever, as long as the content they link to (like a URL) stays live.
What does "error correction level" do?
Higher error correction levels let a scanner still read the code when part of it is damaged, dirty, or covered by a logo. Low (7%) gives the smallest pattern; High (30%) survives heavy damage but makes the code denser.