How a Wi-Fi QR code works
A Wi-Fi QR code is a short line of text in a fixed format. When a phone camera reads it, the phone offers to join the network, so your guests never type a long password. The format was popularised by the open-source ZXing barcode project, and its Barcode Contents page (opens in a new tab) describes it for Android and iOS 11 and later. A home network looks like this:
WIFI:T:WPA;S:mynetwork;P:mypass;;
T is the security type: WPA for almost every home and office network today, WEP for very old routers, or nopass for an open network. S is the network name (the SSID) and P is the password. An optional H:true marks a hidden network that doesn't appear in the Wi-Fi list. Two semicolons end the code.
Because the semicolon, colon, comma, quote and backslash have a meaning inside the code, they must be escaped with a backslash when they appear in your network name or password. A café network called Cafe:Guest becomes S:Cafe\:Guest;. This is the step most generators get wrong, and a single missing backslash is enough for a phone to try the wrong password. This page escapes every special character for you and never trims, quotes or changes what you typed. Korean and emoji names are stored as UTF-8 bytes, the way phones expect them.
T:WPA also covers WPA2 and WPA3. The Wi-Fi Alliance's WPA3 specification says the value "WPA" means password-based security, as quoted by this write-up on Wi-Fi QR codes (opens in a new tab), so a WPA3 router still gets T:WPA. Before you print, press Verify this QR: the page reads its own image back and shows what a phone will see, with the password masked.
Which phones can scan it
On an iPhone, open the Camera app in Photo mode and point it at the code, or use Code Scanner from Control Center, as Apple describes (opens in a new tab). A banner appears; tapping it joins the network. On Android, the camera or the Wi-Fi settings screen reads the same code. Google documents the opposite direction too: an Android phone can show its own Wi-Fi QR code (opens in a new tab) from Settings → Network & internet → Internet → your network → Share. Exact menus may vary by phone.
Apple devices can also share a password between each other without any code, but only if both are Apple devices, Bluetooth is on and each person is in the other's contacts (Apple's requirements (opens in a new tab)). A printed card works for everyone else: Android guests, new visitors and anyone who isn't in your contacts. If you have a Wi-Fi QR and want to see the password inside it, use the Wi-Fi QR scanner.
Printing and placing the card
Pick the format for where the card will live. The table tent prints on one A4 or Letter sheet. The top half is printed upside down on purpose: fold it in half between the small marks at the edges with the print outside, stand it up, and both sides read the right way. It suits a café counter, a reception desk or a dining table. The A6 card (105 × 148 mm) fits a small frame or a fridge magnet sleeve, and 4 × 6 in is the standard photo print size, so you can also save the PNG and print it at a photo kiosk.
Print at 100% ("Actual size") rather than "Fit to page" so the QR code keeps its size. Every design keeps the code at least 35 mm wide, black on white, with a clear margin around it: phones need that quiet zone to find the code. Put the card at eye level or on the table where people sit, not behind glare from a window, and test it once with your own phone. Browse all six looks on the printable templates page.
To make a card last in a busy kitchen or café, slide it into a clear acrylic sign holder or laminate it. Phone cameras read the code through clear plastic as long as the light doesn't bounce straight back, so tilt the stand a little if it does. Keep the PNG on your own phone too: when the printed card goes missing, you can show the code on screen, and a fresh print takes a minute.
Security tips
A printed password is visible to anyone in the room, so print it for a guest network when your router has one. Guest networks keep visitors away from your computers, printers and cameras. If you change the password, make a new card: the old code will stop working. If you'd rather not show the password as text, untick "Print the password on the card"; it stays inside the QR code. A card with a QR code is still a password on paper, so take it down when the party is over.
Privacy matters here because a Wi-Fi password unlocks your home network. Many QR sites send what you type to their server to draw the image. This one doesn't: the QR code is generated by code running in your browser, the downloads are made on your device, and the analytics only count page visits.