QR Code Generator

How the QR Code Generator works

Qr code generator: how the names are built

A QR code is a grid of black and white squares that encodes a short string of data, along with enough redundancy to survive being crumpled, printed badly or partly covered. Everything about the code you see here is decided by two things: how much data you typed, and which error correction level you picked.

Version and size. QR codes come in 40 sizes, called versions. Version 1 is a 21×21 grid holding a handful of characters; version 40 is 177×177 and holds a couple of thousand bytes. This generator picks the smallest version your text fits into, because smaller codes have larger squares at the same print size, and larger squares scan faster and from further away. Shortening a URL before you encode it is the single most effective way to get a code that scans well.

Error correction. Reed–Solomon redundancy is baked into every code, at one of four levels: Low recovers about 7% damage, Medium 15%, Quartile 25% and High 30%. The redundancy is not free — it takes up capacity, so a High code needs a bigger grid for the same text. Medium is the sensible default for anything on a screen or a clean printed page. Go higher if the code will be printed on fabric, curved packaging, or anywhere it might get scuffed, or if you plan to place a logo over the middle of it.

Masking. Large plain areas of black or white confuse scanners, so the encoder tries eight different XOR patterns over the data area, scores each one against the four penalty rules in the specification, and keeps the lowest-scoring result. That is why two codes containing almost the same text can look completely different — a one-character change can flip the winning mask.

The quiet zone. The white border around the code is part of the code. The standard requires four modules of clear space on every side, and scanners genuinely fail without it. The downloaded PNG includes that border, so do not crop tight to the black edge when you place it in a design.

Encoding. Text is encoded in byte mode as UTF-8, which means accented characters, non-Latin scripts and emoji all work — they simply use more bytes each, so they fill a version faster than plain ASCII does. Roughly speaking, an emoji costs four bytes and a Latin letter costs one.

Data types are conventions, not features. A QR code has no idea what it contains — it holds a string. What makes a phone offer to join a network, save a contact or open a map is the shape of that string, and those shapes are conventions the scanning apps agreed on rather than parts of the QR specification. This generator writes them for you: a website becomes a bare https:// URL, a Wi-Fi network becomes WIFI:T:WPA;S:NetworkName;P:password;;, a contact becomes a vCard 3.0 block starting BEGIN:VCARD, an email becomes a mailto: link with the subject and body percent-encoded, an SMS becomes SMSTO:number:message, a phone number becomes tel:, a location becomes geo:latitude,longitude, and a calendar entry becomes an iCalendar BEGIN:VEVENT block.

Escaping. The Wi-Fi, vCard and iCalendar formats all use punctuation as structure, so any semicolon, comma, colon or backslash inside your own values has to be escaped with a backslash or the scanner reads it as the end of a field. A Wi-Fi password containing a semicolon is the classic case, and it is where a lot of generators quietly produce a code that joins the wrong network or fails outright. This one escapes those characters for you, so type the password exactly as it is.

PNG, SVG or an embed snippet. The PNG is the right thing to send to a printer or drop into a document. For a web page, Copy SVG gives you the same code as vector markup — one path element, sharp at any size, a few hundred bytes — that you can paste straight into your HTML or save as a .svg file. Copy img tag wraps that SVG in a data URI inside an <img> element, so it goes into a CMS, an email template or a README with no separate file to host. All three are the same code; only the container differs.

Support varies. Text, URL, phone, SMS and email work essentially everywhere. Wi-Fi and vCard are handled natively by the built-in cameras on current iOS and Android. Calendar events and geo: locations are the least consistent — many phones handle them, some older ones show the raw text instead. Scan-test anything you intend to print, on more than one handset.

There is no tracking, no redirect and no analytics in the codes made here, which also means there is no way to change where one points after you have printed it — the destination is encoded in the squares themselves.

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