QR codes are everywhere now: business cards, menus, billboards, product packaging. But get the size wrong and nobody's scanning your code. Here's everything you need to know about QR code sizing, without the BS.
The Short Answer: How Big Should a QR Code Be?
Minimum size: 2 x 2 cm (0.8 x 0.8 inches)
That's your baseline. Go smaller and most phones will struggle to scan it. But here's the thing, minimum doesn't mean optimal.
The Golden Rule: 10:1 Distance-to-Size Ratio
This is the only formula you need to remember:
QR Code Size = Scanning Distance ÷ 10
Examples:
- Scanning from 50 cm away? Make it 5 x 5 cm
- Billboard 10 meters away? Code needs to be 1 meter wide
- Business card in someone's hand? 2 x 2 cm works fine
This ratio isn't arbitrary. It's based on how smartphone cameras focus and process images. Ignore it at your peril.
Size Requirements by Use Case
Business Cards
- Recommended size: 2 x 2 cm (0.8 x 0.8 inches)
- Why: People hold cards 15-30 cm from their phone
- Pro tip: Don't go smaller. It won't just be hard to scan, it'll look like an afterthought
Posters & Flyers
- Recommended size: 4-6 cm
- Why: Scanning distance is typically 50-100 cm
- Pro tip: Test it at the actual distance people will stand from your poster
Billboards & Outdoor Ads
- Recommended size: 75-100+ cm
- Why: People scan from 7-10+ meters away
- Pro tip: Go bigger than you think. Better too large than too small
Product Packaging
- Recommended size: 2-3 cm
- Why: Close-range scanning when held in hand
- Pro tip: Ensure it's on a flat surface, not a curve
Table Tents & Menus
- Recommended size: 3-5 cm
- Why: Scanning across a table (30-60 cm)
- Pro tip: Consider the natural reach distance at your specific venue
Digital QR Codes (Websites, Screens)
For digital use, think in pixels:
- Minimum: 240 x 240 pixels at 72 DPI
- Recommended: 300 x 300+ pixels for crisp display
- Why: Screens vary in resolution, and you want it to look sharp everywhere
What About Pixel Dimensions?
If you're working in design software:
- Each cm ≈ 38 pixels
- So 2 x 2 cm = approximately 76 x 76 pixels minimum
- But always export at a higher resolution (300+ DPI for print)
The Quiet Zone: Don't Forget White Space
Every QR code needs breathing room. At least 6mm (¼ inch) of clear space on all sides. This "quiet zone" helps scanners distinguish where the code starts and ends.
Skip this and your code might not scan, even if the size is perfect.
Color and Contrast Matter
Size isn't everything. Your QR code needs:
- High contrast: Dark code on light background (not the reverse)
- Minimum contrast ratio: 4:1 for reliable scanning
- Safe bet: Black on white always works
Colored QR codes are fine, but test them extensively. A poorly contrasted code won't scan no matter how big it is.
Common Sizing Mistakes
1. Making It Too Small to Save Space
We get it. You want more room for your design. But a QR code that doesn't scan is useless. Stick to the minimums.
2. Not Testing at Actual Scanning Distance
What looks fine on your computer might be impossible to scan in real life. Always test in the actual environment.
3. Forgetting About Print Quality
Low-resolution exports get pixelated when printed. Always use vector formats (SVG, EPS, PDF) or export at 300+ DPI.
4. Overcomplicating the Code
The more data you pack in, the denser the code becomes. Use URL shorteners to keep codes simple and scannable.
Can QR Codes Be Different Shapes?
Yes, but with caveats.
The functional part of any QR code is always square. You can wrap it in a circle or other shape, but:
- The scannable matrix itself must remain square
- Don't obstruct the position markers (corner squares)
- Keep it simple, weird shapes reduce scannability
There are also rectangular variants (iQR Codes and rMQR Codes) designed for narrow spaces, but standard QR codes are your safest bet.
How to Test Your QR Code
Before you print thousands of business cards or hang that billboard:
- Scan it with multiple phones (iPhone and Android)
- Test at the actual scanning distance
- Try different lighting conditions
- Check that it loads quickly
- Verify the link works
One test scan isn't enough. Get 5+ people to try it.
Bottom Line
Don't overthink it, but don't wing it either:
- Stick to 2 x 2 cm minimum for close-range
- Use the 10:1 ratio for distance scanning
- Leave white space around it
- Test in the real world before you commit
QR codes are one of the simplest ways to bridge physical and digital experiences, but only if people can actually scan them.
