Do QR codes expire? How to make one that never does

A QR code on a poster or a business card has to keep working for years. Whether it will depends on one thing people rarely check when they make it: whether it is static or dynamic.

Static and dynamic QR codes

• A static QR code stores your content — the web address, the text, the Wi-Fi details — directly in the pattern. A phone reads it and goes straight there. There is nothing in between that can expire.
• A dynamic QR code stores a short link belonging to the service that made it. Scanning it visits that service, which forwards the visitor to your real address. That allows scan counts and editing the destination later — but if the service shuts down, or the plan lapses, the short link stops working and so does every printed copy of your code.

So QR codes themselves do not expire. Dynamic codes can stop working because they depend on someone else's server.

How to tell which kind you have

Scan the code and look at the address your phone shows before you tap it. If it is your own address — your website, your menu, your booking page — the code is static. If it is a short link on a domain you do not recognise, the code is dynamic, and it will only work for as long as that domain keeps forwarding it.

This is worth checking before anything goes to print. Some generator sites create dynamic codes by default and switch them off when a free trial ends unless you subscribe. People usually discover this after the flyers have been handed out, when the code starts leading to a payment page instead of their menu.

Make a QR code that never expires

1. Open the QR Code Generator.
2. Choose what the code holds: a link, plain text, an email, a phone number, an SMS or Wi-Fi details.
3. Fill in the fields; the code redraws as you type.
4. Download it as PNG for screens and documents, or SVG for print and anything large.

These codes are static: your content is in the pattern itself, with no redirect, no account, no watermark and no expiry. They keep working even if this site disappears.

When a static code can still stop working

The code never changes, but the thing it points to can. A static code fails when the page it links to is deleted or moved, when the domain name is not renewed, or — for a Wi-Fi code — when the network password changes. None of that is the code expiring; the destination has gone.

You can protect yourself and keep the code static. Point it at an address on a domain you control, and choose one you can keep stable, such as yoursite.com/menu rather than a link to this season's PDF. When the menu changes, update what that page shows. The printed code carries on working because the address it holds never changed.

What you give up

A static code cannot be edited after printing, and it cannot count scans. If you need to know how many people scanned a poster, point the code at a link tagged with the UTM Link Builder and your website analytics will count the visits — without any third-party redirect.

Dynamic codes are not a trick; they solve a real problem. If you are printing something at large scale and genuinely need to repoint it later to addresses you cannot predict, or you need scan reports without running analytics on your own site, a paid dynamic service does that. Go in knowing the terms: what it costs each year, what happens to existing codes if you stop paying, and whether you can export or move them.

Print it so it always scans

• Dark on light. Inverted codes (light on dark) fail on many scanners, and low contrast fails on all of them.
• Keep the margin. The empty border around the pattern, called the quiet zone, is part of the code. Do not crop it or print over it.
• Size for the distance. A common rule of thumb is that a code can be scanned from about ten times its own width, so a 3 cm code works at arm's length and a poster read from across a room needs a much bigger one.
• Keep the content short. The more you encode, the denser and harder to scan the pattern becomes.
• Raise error correction for tough conditions. Level L recovers about 7% damage, M 15%, Q 25% and H 30%. Use H for small prints, curved surfaces, or a logo in the middle.
• Test the printed code with two or three different phones before printing hundreds.

How much a QR code can hold

A QR code is a grid of small squares called modules. The smallest version is 21 modules on each side and the largest is 177, and the generator picks the smallest grid that fits your content at the error-correction level you chose. In theory the largest grid holds about 4,300 letters and digits. In practice a code that dense is hard for a phone to read, so keep the content under a couple of hundred characters.

This is the practical reason to shorten what you encode. A long address with tracking parameters produces a fine, dense pattern that needs to be printed large; a short address produces a coarse pattern that scans from further away and survives a poor print. As a minimum, print a code holding a short link at about 2 cm across for something held in the hand, and scale up from there using the ten-times rule.

Adding a logo

A logo in the middle works because of error correction: the scanner rebuilds the covered modules from the redundant data. Set error correction to H and keep the logo under about a fifth of the code's width. Leave the three large corner squares completely clear — the scanner uses them to find and orient the code, and they cannot be reconstructed. Then test it on several phones, because a logo spends the safety margin that would otherwise cover scuffs and bad lighting.

Wi-Fi codes for guests

A Wi-Fi QR code lets guests join your network by pointing their camera at it. The Wi-Fi and vCard QR Code Generator makes one — enter the network name, password and security type exactly as your router shows them — and lays it out as a printable card.

Remember that a Wi-Fi code contains the password in readable form: anyone who scans it can see it. Display it only where you would be happy to write the password on the wall, and make a new code whenever you change the password.

Scanning other people's codes safely

The same directness that makes static codes reliable means a code can point anywhere. Before you open a scanned link, read the address your phone shows. Be wary of a sticker placed over another code on a parking meter, a menu or a poster, and of any code that leads to a page asking for a password or card details. A QR code is only a way of typing an address for you; treat the address with the same care as a link in an email.