Make a QR code: for a link, a few words, a phone number or an email address

What is inside the code

• Only what you typed. The page shows it under “The code holds exactly this”. There is no address of ours inside and nothing in between: reading the code does not pass through this site, so nobody here can see or count who reads it.
• It does not run out. The code is a picture of your text. It works for as long as the link, the number or the address inside it works.
• It cannot be changed later. To send people somewhere else, make a new code and print it again.
• Anyone who sees the code can read it. Put nothing in it that you would not write on the same paper in plain letters: no password, no card number.

Before you print many

• Try it with your own phone first. Point the camera at the code on this screen, or at one printed sheet. This page has been tried with a reader program, not with a real phone camera.
• What a phone does with the code is up to the phone. The page writes a phone number as a link that begins with tel: and an email address as one that begins with mailto:. One phone may offer to call or to write; another may only show the text.
• Keep the white edge. The light border around the squares is part of the code. Do not cut it off or print over it.
• Shorter is bigger. A short text makes a code with fewer squares, so each square prints larger on the same paper. The smallest code here is 21 by 21 squares and the largest is 57 by 57.
• Let people see where it leads. The page can print what the code holds under it, in plain letters.

What you can change

• What it holds: a link, a few words, a phone number or an email address, up to 213 bytes. A plain letter, a digit or a space is one byte; a letter with an accent is two; an emoji is four.
• The words above it: up to 60 characters, printed in plain letters. They are not inside the code.
• How many: one big code, or 12 small ones on a sheet to cut apart.
• A picture: the code alone, saved as a file named qr-code.png, to put on a flyer or in a message.

What this page does not do

• It keeps nothing. What you typed is gone when you close or reload the page.
• It does not read codes, and it cannot tell you where someone else’s code leads. If a code you did not make opens a page that asks for money, a password or a code sent to your phone, stop and open Is this a scam?
• It does not check your link. An address typed wrong makes a code that leads to the wrong address.
• It does not make codes that join a Wi-Fi network or save a contact, and it adds no colors and no logo.
• It does not mark the letters. Accents and emoji go in as UTF-8 bytes, with no note inside the code saying so. The reader program used here read them back as typed; a phone might show them differently.
• It has been tried in one browser’s print preview (Chromium, saved as PDF), not on paper from a real printer.

Every time the page is built, a program checks 38 examples worked by hand. Then it makes a code for every length from 1 to 213 bytes and for 2,000 made-up texts, and a reader program written by other people (zxing-cpp) reads each one back and has to get the same bytes. It also draws 250 more texts in 8 ways each, and every square of those 2,000 drawings has to match a second program that makes QR codes (segno). That checks the page’s own work, not your link.