Last month, I watched a woman at a bus stop try to scan a QR code on an advertisement for about 45 seconds before giving up. The code was too small, printed on glossy paper that reflected the sunlight, and crammed into a corner of the ad. That company paid good money for that billboard space, and they're getting almost zero scans because of basic design mistakes.

I've been designing marketing materials for about eight years now, and I've seen QR codes go from "that weird tech thing" to absolutely everywhere. But here's what drives me crazy: most people still don't know how to design them properly. So let me share what actually works, based on real testing and plenty of failures.

The Size Thing Everyone Gets Wrong

Here's the rule I follow: your QR code should be at least 1 inch (2.5 cm) square for every 10 inches (25 cm) of scanning distance. So if someone's going to scan it from 3 feet away, you need roughly a 3.5 inch code.

But honestly? I usually go bigger than that. A QR code that's too large is annoying. A QR code that's too small is invisible. I'd rather err on the side of "too big."

I learned this the hard way with a client's product packaging. We made these beautiful, minimalist labels with tiny QR codes - maybe half an inch square. They looked great in the design mockups. In real life? People couldn't scan them without perfect lighting and steady hands. We had to recall and reprint thousands of labels.

Now I do this: I print a test version at actual size, put it where it's going to be used, and try to scan it from the actual distance people will be standing. Sounds obvious, but you'd be surprised how many designers skip this step.

Contrast Isn't Just Black and White

Everyone knows you need contrast between the QR code and its background. But there's more to it than just "dark on light."

I've tested QR codes in probably 20 different color combinations. Here's what I've found:

Black on white works best. Not because it's traditional, but because phone cameras handle high contrast better in varied lighting conditions. It just works.

Dark blue, dark green, or dark purple on white also work well. I use these when the brand colors demand it. The key is that the dark color needs to be really dark - like 80% or darker if you're thinking in terms of color values.

What doesn't work: Light colors on dark backgrounds. I know it looks cool and modern, but phone cameras struggle with it, especially in dim lighting. I've seen scan rates drop by 60% or more just from inverting the colors.

The glossy paper problem: This is huge and nobody talks about it. If you print a black QR code on glossy white paper, it can create glare that makes scanning difficult. I always request matte or satin finish for anything with a QR code. If you must use glossy, test it in direct sunlight before you print 10,000 copies.

The Quiet Zone (And Why It Matters More Than You Think)

The quiet zone is the white space around your QR code. The technical spec says it should be 4 modules wide (a module is one of those little squares in the code).

In practice, I make it bigger - usually about 1/4 inch of clear space on all sides. Why? Because QR codes don't exist in a vacuum. There's usually other design elements nearby, and phone cameras need that buffer to figure out where the code starts and ends.

I worked on a menu design where the client wanted to maximize space, so they put the QR code right up against the edge of a colored box. Technically, there was enough quiet zone. But the scan rate was terrible because the phone cameras kept trying to include the colored box as part of the code.

We added more white space, and scans went up by about 40%. Sometimes the old rules exist for good reasons.

Placement: The Thing That Matters Most

You can have a perfectly designed QR code that nobody scans because it's in the wrong place. Here's what I've learned:

Eye level is ideal. People don't want to crouch or stretch to scan something. If you're putting a QR code on a poster, put it in the middle or lower third, not at the top.

Consider the scanning angle. I once put a QR code on a table tent at a restaurant. Looked great in the mockup. In reality, people sitting at the table had to hold their phones at a weird angle to scan it because the tent was angled toward them. We moved the code to a flat card instead.

Think about the context. QR codes on moving vehicles? Terrible idea - nobody can scan them. QR codes on a checkout counter where people are standing still? Perfect. QR codes on a billboard next to a highway? Only works if there's traffic.

The phone-in-hand test: Before finalizing any placement, I literally stand where a user would stand, hold my phone like I'm going to scan, and see if it feels natural. If I have to contort my arm or move to a different position, the placement is wrong.

Error Correction: Your Safety Net

QR codes have built-in error correction, which means they can still work even if part of the code is damaged or obscured. There are four levels:

• L (Low): 7% of code can be damaged
• M (Medium): 15% can be damaged
• Q (Quartile): 25% can be damaged
• H (High): 30% can be damaged

I almost always use H (high) for printed materials. Yes, it makes the code slightly more complex, but it means the code will still work if it gets a little dirty, worn, or if someone puts a logo over part of it.

For digital displays where the code will always be pristine, M is fine. But for anything that's going to be outside, handled frequently, or exist for more than a few months, go with H.

The Logo Question

People always ask: "Can I put my logo in the middle of the QR code?"

Yes, but carefully. The error correction I mentioned above is what makes this possible. Here's my approach:

Keep the logo small - it should cover no more than 20% of the total code area. I usually aim for 15% to be safe.

Use high error correction (level H) when adding a logo.

Test extensively. I test codes with logos on at least 5 different phones before approving them. Sometimes a logo that works fine on iPhone has issues on Android, or vice versa.

Consider if you really need it. Sometimes a logo in the QR code looks cool but doesn't add much value. If the code is already on your branded materials, maybe you don't need the logo inside the code too.

Color Customization (Proceed with Caution)

You can customize QR code colors, but it's riskier than most people think. Here's my hierarchy:

Safest: Black code on white background Pretty safe: Very dark color on white background Risky: Light color on dark background Very risky: Low contrast combinations, gradients, or patterns

I've had clients insist on brand colors that just don't work for QR codes. When that happens, I show them the scan rate data. A beautiful QR code that nobody can scan is worthless.

If you must use custom colors, test them in multiple lighting conditions. What works indoors might fail in sunlight. What works in sunlight might fail in dim restaurant lighting.

The Call-to-Action Nobody Remembers

This isn't technically about the QR code design itself, but it's crucial: tell people what they're going to get when they scan.

"Scan for menu" works way better than just a QR code sitting there. "Scan to enter contest" gets more scans than an unlabeled code.

I did an A/B test with a client where we added a simple "Scan me" label with an arrow. Scans increased by 80%. People need that little nudge.

Testing: The Step Everyone Skips

Before you print anything, test your QR code:

On multiple devices: iPhone, Android, older phones if possible. Camera quality varies a lot.

In different lighting: Bright sunlight, dim indoor lighting, fluorescent lights. Each one can affect scanning.

At the actual distance: If it's going on a wall, tape it to a wall and scan it from where people will actually be standing.

After printing: Print one test copy on the actual material you'll use. The printing process can sometimes affect scannability, especially if the printer's alignment is off.

I keep a folder of QR code failures - codes that looked great in design but failed in real-world testing. It's a good reminder that what works on a computer screen doesn't always work in practice.

Common Mistakes I See Constantly

Putting QR codes on curved surfaces: The code needs to be flat for cameras to read it properly. I've seen codes on coffee cups, water bottles, even curved signs. They're nearly impossible to scan.

Using QR codes in videos or GIFs: Unless the video pauses on the code for several seconds, nobody can scan it. I've seen this in TV commercials and it's just wasted opportunity.

Making them too decorative: I get it, plain QR codes aren't exciting. But every design element you add increases the risk of scanning failures. Function over form here.

Not updating them: This is more of a management issue, but I've scanned QR codes that lead to 404 errors or outdated content. If you're going to use QR codes, commit to maintaining them.

My Design Checklist

Before I approve any QR code design, I run through this:

• Is it at least 1 inch square? (Bigger if scanning distance is greater)
• Is there at least 1/4 inch of white space around it?
• Is the contrast ratio high enough? (I aim for at least 4:1)
• Does it scan on both iPhone and Android?
• Does it scan in bright light and dim light?
• Is there a clear call-to-action?
• Is the destination mobile-friendly?
• Have I tested it at the actual size and placement?

If I can't check all those boxes, something needs to change.

The Bottom Line

QR codes are incredibly useful, but only if people can actually scan them. I've seen too many businesses waste money on QR code campaigns that fail because of basic design mistakes.

The good news is that getting it right isn't complicated. Make it big enough, ensure good contrast, leave white space, test it thoroughly, and put it somewhere people can actually scan it comfortably.

Do those things, and your QR codes will work. Skip them, and you're just putting decorative squares on your marketing materials.