Guides
QR code guides, tested rather than guessed
Written by the team that builds the generator on this site — and corrected whenever our own measurements proved us wrong.
There is no shortage of QR code advice online, and a lot of it is repeated rather than tested. These guides take the opposite approach: each one deals with a problem we hit building this tool, and every claim about whether something scans comes from rendering a code and decoding it back.
Where the results contradicted what we expected, we have said so. Three of our own design presets failed our first round of testing, and five corner shape combinations turned out to be completely unreadable — findings that now drive warnings in the generator itself.
What you'll learn here
- How to diagnose an unscannable code in about five minutes, in the order worth checking.
- Exactly how far shapes, colours and logos can be pushed before a decoder gives up.
- Whether a static or dynamic code fits your situation, and the middle path most people miss.
- What makes people actually scan a code in a shop or restaurant, which is rarely the design.
Latest
QR code security: what a code can and cannot tell you
A QR code hides its destination until scanned, which is exactly what makes malicious codes effective. As a publisher, use your own domain so people can recognise it. As a scanner, always read the URL your phone shows before tapping, and be suspicious of stickers placed over existing codes.
GuidesQR codes on product packaging
Packaging codes have to survive printing on awkward materials and stay useful for years. Both constraints change what you should encode.
GuidesGenerating QR codes in bulk
Hundreds of asset tags, tickets or per-product links. How to generate them reliably, and how to verify a batch without checking each one by eye.
GuidesQR codes for events, tickets and badges
Event codes get scanned fast, in bad light, by tired staff. What that means for size, contrast and the payload you choose.
GuidesQR codes on business cards that people actually scan
Card codes are among the smallest anyone prints, which makes payload length the decisive factor. What to encode, how big, and where to put it.
GuidesPNG, SVG, PDF or JPG: which QR code file to download
Vector for print, raster for screens, and never JPG if you can avoid it. The differences matter more for QR codes than for ordinary images.
GuidesWhich QR code type should you use?
URL, Wi-Fi, vCard, SMS, calendar, payment — the type decides what the phone offers to do. A short guide to picking the right one.
GuidesWi-Fi QR codes: the one most venues never print
A Wi-Fi code replaces a conversation, a password on a chalkboard and a staff interruption. It is also the type most likely to be silently broken.
GuidesQR codes or NFC tags?
They solve overlapping problems with very different failure modes and costs. When a printed square beats a chip, and when it does not.
DesignTransparent backgrounds and where they go wrong
A transparent QR code is convenient right up until it lands on something dark. What transparency actually does, and which formats keep it.
DesignCustom corner shapes: the restyling that breaks codes
Module shapes are forgiving. The three corner patterns are not. We tested all 36 combinations and five of them never decoded at all.
GuidesvCard or MeCard for a contact QR code?
Both put your details into someone's phone. One produces a code roughly twice as dense as the other, which decides how well it scans off a business card.
GuidesWhy shortening the URL is usually the best fix for a QR code
Fewer characters means fewer modules, and bigger modules scan better. Shortening a link is often more effective than enlarging the code.
DesignGradients in QR codes: what works and what quietly fails
Gradients are safe in principle and one of the most common causes of a beautiful, unscannable code in practice. The rule is simple once you see it.
DesignPutting a logo in a QR code without breaking it
A centre logo is the most requested customisation and the easiest way to ruin a code. The size limit, the error correction rule, and how to check you got away with it.
DesignChoosing QR code colours that actually scan
Colour is the most common cause of unscannable codes, and the hardest to spot by eye. What contrast really means here, and which palettes fail.
TroubleshootingQR code error correction levels, explained
L, M, Q and H decide how much damage a code survives — and how big it gets. Here is how to pick one deliberately instead of leaving it on the default.
TroubleshootingThe quiet zone: the margin that breaks more codes than anything else
The empty border around a QR code is part of the code. Crop it and you get something that scans in the studio and fails on the poster.
TroubleshootingHow big should a QR code be?
Sizing is not guesswork. The distance people scan from sets the minimum, and the length of your content quietly changes the answer.
TroubleshootingSix reasons your QR code is not working
Almost every unscannable QR code fails for one of six reasons. Here is how to spot which one you have hit, and the fix for each.
TroubleshootingQR codes on curved, glossy and awkward surfaces
Bottles, laminates, fabric and folds each break codes in their own way. What to do when the material is not flat white card.
TroubleshootingHow to test a QR code before you print a thousand of them
A five minute checklist that catches nearly every failure, and the specific tests worth running before a print run rather than after.
GuidesStatic vs dynamic QR codes: which one do you actually need?
Dynamic codes buy you editable destinations and scan analytics. They also buy you a subscription and a single point of failure. An honest comparison.
DesignDesigning QR codes that still scan
Rounded modules, gradients and custom corners are all safe — within limits. Here is exactly where those limits sit, measured rather than guessed.
GuidesQR codes for restaurants and retail that people actually scan
Placement and wording move the numbers far more than design does. Practical notes on what gets scanned and what gets ignored.
Questions, answered briefly
- Why won't my QR code scan?
- Check contrast first, then the quiet zone, then logo size. Those three account for the large majority of failures, and all three are things you can verify before printing anything.
- Should I use a static or a dynamic QR code?
- Static unless the destination genuinely has to change on a shorter timescale than the printed item will last. If you want editability without a subscription, point a static code at a redirect on your own domain.
- How much can I customise a code before it breaks?
- More than most people expect on shapes and colours, and less than most people expect on the three corner patterns. A logo can cover about a quarter of the width at error correction level H.
Browse by topic
Scannability
The practical engineering of getting a code to read reliably, off paper, in bad light, on someone else's phone.
Design
How far you can push shape, colour and branding before a decoder stops finding your code.
Choosing a code type
Static or dynamic, and which payload format actually does what you want.
Formats and tooling
The technical side: which file to download, how to generate at volume, and what a QR code can and cannot tell you.
Business use
Placement, wording and payload choices for venues, retail and print campaigns.
Who writes this
We build and test the QR generator on this site. Everything we publish about QR codes comes from measurements we ran ourselves against real encoders and decoders, not from summarising other people's articles.
How we test everything