Static vs Dynamic QR Codes, and Why Yours Is Not Scanning

The real difference between static and dynamic codes, how to get most of the benefit of a dynamic one for free, and the nine reasons a printed code fails to scan.

A static QR code holds the destination inside the pattern itself and cannot be changed once it is made. A dynamic QR code holds a short redirect address, so the destination behind it can be changed later — and stops working if whoever runs that redirect stops running it.

That trade is the whole decision, and there is a way to get most of the benefit without paying for either.

What is the difference between a static and a dynamic QR code?

The pattern is what differs. In a static code the destination is encoded in the black and white squares, so the code is the link. In a dynamic code the squares encode a short address belonging to a QR service, which forwards the visitor to wherever that service currently points it.

What follows from that:

• Static — free, permanent, works forever, needs no account and no company to stay in business. The destination can never change, and it cannot count scans.
• Dynamic — the destination can be changed after printing, and scans can be counted. It depends on a third party staying alive and, usually, on a subscription being paid. If either stops, every printed code stops working.

A dynamic code also produces a simpler pattern, because a short redirect address is less data than a long URL. That can matter when a code has to be printed small.

Which one do I need?

Static, in most cases. Dynamic only when you genuinely need one of the two things it adds:

• You need to change the destination after printing. A menu that moves, a campaign that redirects somewhere different next month, ten thousand printed flyers you cannot reprint.
• You need scan analytics. How many, when, roughly where.

If neither of those is true, a dynamic code adds a dependency and a bill in exchange for nothing.

How do I get the benefit of a dynamic code without paying for one?

Point a static QR code at a URL you already control, and change what is behind that URL.

This is the technique most people miss. A static code encoding yoursite.com/menu is permanent and free, but the page at /menu is yours — so you can redirect it, rewrite it, or point it at a different PDF whenever you like. The code never changes because it never has to.

Two things to get right:

• Use a path you will not regret. /menu will still make sense in three years. /summer-promo-v2 will not.
• Never point a permanent code at a free link shortener. Shorteners disappear, get bought, or start showing interstitials, and when one does, every printed code pointing at it dies at once. A domain you own does not have that failure mode.

The one thing this does not give you is scan counts. Server logs or analytics on the destination page get you most of the way.

Why is my QR code not scanning?

Nine reasons, most common first:

• Too little contrast. The code needs to be clearly dark on clearly light. Light grey on white, or a code printed over a photograph, will fail on half the phones that try.
• Inverted colours. A light code on a dark background breaks many scanners, which expect dark modules on a light field.
• No quiet zone. The specification requires a clear margin of four modules — four "squares" of empty space — all the way round. Codes cropped tight to the pattern, or butted against other artwork, fail.
• Printed too small for the distance. See below.
• Too much data. A long URL makes a dense pattern with tiny modules. At small print sizes those modules blur together. Shorten the link.
• A logo covering too much of it. Error correction tolerates some obstruction, but a large logo in the middle passes the limit and the code stops decoding.
• Blur, glare or curvature. A code on a glossy laminate under a spotlight, or wrapped round a bottle, may be unreadable at some angles.
• Damage or low print quality. Bleeding ink on absorbent paper thickens the modules and closes the gaps between them.
• The destination is broken. The code scans and the page 404s. Always test the whole journey, not just the scan.

Test before printing, on more than one phone, at the size and distance it will actually be used — and from a printed proof rather than from a screen.

How big does a QR code need to be?

The usual rule of thumb is that scanning distance is about ten times the width of the code. A code 3cm across is comfortable at roughly 30cm; a poster meant to be scanned from three metres wants a code around 30cm.

Add margin to that if the code will be scanned in poor light, at an angle, or by older phones. And remember the quiet zone is part of the required size, not spare space you can trim.

What is the quiet zone?

The quiet zone is the empty margin around a QR code, and the specification sets it at four modules wide on every side. A module is one of the small squares the pattern is built from.

It exists so a scanner can tell where the code ends. Designers crop it away constantly because it looks like wasted space, and it is the most common reason an otherwise perfect code fails.

Does a QR code expire?

A static QR code never expires. It is a printed representation of a piece of text and will decode in fifty years.

What expires is everything behind it — the domain, the hosting, the page, or the subscription to whichever service issues a dynamic code. When people say a code stopped working, one of those is almost always what happened.

QR code best practices

• Point it at something that will still exist. Prefer a URL on a domain you own.
• Keep the encoded data short. Short link, simpler pattern, more reliable scan.
• Keep the quiet zone.
• Keep strong contrast, dark on light.
• Test a printed proof at real size and distance, on more than one phone.
• Tell people what it is for. "Scan for the menu" outperforms a bare code.
• Give a fallback — a short printed URL under it — for anyone whose camera will not cooperate.
• If you add a logo, keep it small and re-test.

Lonecto's QR code generator makes static codes in the browser: your data is encoded into the pattern and nothing is stored or tracked by us. That means they are permanent and free forever, and it means they cannot be re-pointed later — so use the technique above and aim them at an address you control.

Questions

Are free QR codes safe to use? A static code is just a printed piece of text and carries no ongoing risk. Be careful with free dynamic codes: the destination is controlled by whoever issues them, and some free tiers begin redirecting or expiring later.

Can somebody change where my QR code goes? Not a static one — the destination is in the pattern. A dynamic one can be changed by whoever controls the account it was made in.

Do QR codes work without internet? The scan works offline; the code is decoded on the phone. Opening the link it contains needs a connection. A code containing plain text or wifi details works entirely offline.

Why does my code scan on one phone and not another? Usually contrast, size or the quiet zone, all of which push a marginal code over the edge on a weaker camera. If a code only works on the newest phone in the room, it is too marginal to print.

Should I put a logo in the middle? You can, and keep it small. Error correction can rebuild some of a covered code, but every obstruction eats into the tolerance you would rather spend on print quality and scuffs.

Is a shorter link really worth it? Yes. Less data means fewer, larger modules, which survives small printing, poor light and cheap cameras far better.