Make it, size it, scan it back: three QR code tools that stay in the browser

A QR code looks like a one-step job: paste a URL, save the image. The problems show up later — the printed code is too dense to scan from across the room, the Wi-Fi code does not connect because the password had a semicolon in it, or someone hands you a code and you would like to know where it goes before your phone opens it. Omikuji Tools has three small pages for the three halves of that job, and none of them send your data anywhere.

QR Code Maker

The generator has tabs for a URL or plain text, Wi-Fi, a contact card (vCard) and a calendar event, plus a batch mode: paste up to 500 lines from a spreadsheet and every line becomes its own code, downloaded together as a ZIP. Single codes save as PNG or SVG. You can change the foreground and background colours, the margin and the error-correction level, and composite a logo in the centre (the page tells you to switch to level H when you do).

The detail I like most is the Encoded String panel under the preview. It shows the exact text that went into the code, so for Wi-Fi you can see that characters like ;, , and : in the network name or password were escaped the way the WIFI: format expects. A Wi-Fi code that silently fails to connect is usually that.

QR Code Capacity Chart

This one answers "why is my code so dense?". Paste a string and it tells you which encoding mode it lands in, the smallest version (1 to 40) that fits at your chosen error-correction level, the module count and how many characters you have left. Pick a module size in millimetres and it gives the printed size, including the four-module quiet zone a QR code needs on every side.

It also explains a small trick: alphanumeric mode only covers 45 characters — digits, uppercase A–Z, space and $ % * + - . / :. A single lowercase letter pushes the whole string into byte mode, which holds less, and that is why an all-caps URL can sometimes drop a version. The capacity figures are measured by packing data into a real QR library and searching for the largest string that fits, not copied from a table.

QR Code Reader

The reader takes an image by drag and drop, file picker or Ctrl / Cmd + V, several images at once, or a live camera feed (rear camera preferred). Decoding is done with jsQR inside the page. If the first attempt fails it retries at several scales, with the colours inverted and with the contrast stretched.

It never opens a link on its own. A URL is shown in full with its domain pulled out and a warning to check it first — QR phishing works precisely because you cannot see the destination. Wi-Fi codes are broken down into SSID, encryption type and a password that stays masked until you ask. The last 20 results are kept in your browser's local storage, with a button to clear them on a shared machine.

👉 QR Code Maker — free, no sign-up, generated on your device. 👉 QR Code Capacity Chart — versions, modules and print size for any string. 👉 QR Code Reader — images and camera frames never leave the browser.

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