How to Make a QR Code That Scans Every Time (Wi-Fi, UPI, Contact Card)
QR codes are everywhere: on menus, shop counters, posters, business cards and invoices. Making one takes seconds, but making one that scans reliably, in poor light, from a distance, on a printed page, takes a little care. This guide covers how QR codes work, how to make the most useful kinds and how to avoid the mistakes that stop them scanning.
What a QR code actually contains
A QR code is just text encoded as a pattern of squares. A phone camera reads the text and the phone decides what to do with it, based on how the text starts. Text beginning with https:// opens in the browser. Text beginning with WIFI: offers to join a network. A block starting with BEGIN:VCARD offers to save a contact, and text starting with upi://pay opens a UPI app with the payment details filled in. That is why one generator can make many kinds of codes.
Static codes never expire
Codes made here are static: all of the information is inside the pattern. They work forever, do not rely on any website staying online and cannot be switched off by anyone. The trade-off is that a printed static code cannot be changed. If your menu link or phone number may change, point the code at a page you control, or be ready to reprint.
Making the most useful codes
A link to your website
Choose Website and enter the address. If you leave off the https:// part, it is added for you. Shorter addresses make simpler codes that scan faster, so use a short link for a long address.
A Wi-Fi code for guests
Enter the network name exactly as it appears, choose the security type (most home routers use WPA or WPA2) and enter the password. Guests scan the code and join, with no typing. Print it and put it where guests will see it, such as on the fridge or the guest-room wall.
A UPI payment code
Enter your UPI ID and the name you want payers to see. Add an amount only if every payment will be for the same sum. Before you print or display the code, scan it with a UPI app and send a small test payment to yourself or a friend, to confirm that the name and account are right.
A contact card
Enter your name, phone, email, company and address. Scanning offers to save you as a contact. It is a good fit for business cards, and a short card with only the essentials scans most easily.
Make it scan reliably
- Use a dark code on a light background. Many scanner apps cannot read inverted codes (light on dark).
- Keep strong contrast. Pale grey on white or yellow on white is hard to read, and the generator warns you when contrast is low.
- Do not remove the white margin around the code. It helps the camera find the edges.
- Make it big enough. As a rule of thumb, a code can be scanned from about ten times its width, so a 2 cm code works at about 20 cm, and a poster code that people scan from 2 metres needs to be around 20 cm wide.
- Test with at least two phones, in the lighting where the code will be used, before you print many copies.
Error correction explained
QR codes include built-in redundancy, so a code can still be read when part of it is dirty or damaged. There are four levels:
| Level | Can recover from about | Best for |
|---|---|---|
| L | 7% damage | Clean screens, very long content |
| M | 15% damage | Everyday use (the default) |
| Q | 25% damage | Printed items that may get scuffed |
| H | 30% damage | Rough surfaces, stickers, outdoors |
Higher levels make the code denser, with more, smaller squares, which is harder to scan when printed small. Choose the lowest level that fits your situation, and if you raise it, make the code larger.
PNG or SVG?
Download PNG for web pages, chat messages and documents. Download SVG for print, such as posters, packaging and signage, because it is a vector format that stays perfectly sharp at any size, so the squares never turn blurry.
The details you type into a QR generator are sent to its server to draw the code. Do not make codes containing secrets you would not want a service to see, and remember that anyone who scans a code can read what is inside it.
Tools mentioned in this guide
- QR code generator: Make a QR code for a link, text, Wi-Fi login, contact card, UPI payment and more, then download it as PNG or SVG.
- Compress image: Make photos and images smaller for the web or email while keeping them looking good.
- Word, character & sentence counter: Count words, characters, sentences and paragraphs, and see reading and speaking time.