Complete Guide to QR Codes: Create, Customize, and Use

What Is a QR Code

A QR code (Quick Response code) is a two-dimensional barcode that stores data in a grid of black and white squares. Invented by Denso Wave in 1994 for tracking automotive parts in Japanese factories, QR codes have become a universal bridge between the physical and digital worlds.

When you scan a QR code with your phone's camera, the pattern is decoded into data — a URL, text, contact information, WiFi credentials, or any other string of characters. The maximum capacity is 4,296 alphanumeric characters or 7,089 numeric digits, enough for most practical uses.

How QR Codes Work

A QR code consists of several functional areas:

Finder patterns — The three large squares in the corners. These help scanners detect the QR code's position and orientation. You can scan a QR code at any angle, upside down, or even partially obscured because of these anchor points.

Alignment patterns — Smaller squares distributed across the code that help correct for perspective distortion (e.g., scanning at an angle).

Timing patterns — Alternating black and white stripes between finder patterns that help the scanner determine the grid size.

Data and error correction — The rest of the code contains the actual data plus Reed-Solomon error correction codes. QR codes can recover from up to 30% damage (the "H" error correction level), which is why they still scan even when partially covered by a logo.

Error correction levels:

| Level | Error Recovery | Data Capacity | Best For | |---|---|---|---| | L (Low) | 7% | Maximum data | Digital-only use (screens) | | M (Medium) | 15% | Standard | Most printed codes | | Q (Quartile) | 25% | Reduced | Codes in harsh environments | | H (High) | 30% | Minimum | Codes with embedded logos |

Static vs. Dynamic QR Codes

This is the most important distinction to understand:

Static QR Codes

The data is encoded directly into the QR code pattern. A static QR code pointing to https://example.com will always point to that URL. It cannot be changed after creation.

Pros:

• No dependency on any service — works forever
• No tracking — the scan goes directly to the destination
• Free to create with no ongoing costs
• Complete privacy — no third party involved

Cons:

• Cannot change the destination after printing
• No scan analytics

Dynamic QR Codes

A dynamic QR code contains a short redirect URL (like https://qr.service.com/abc123). When scanned, the redirect service forwards to the actual destination. The destination can be changed at any time through a dashboard.

Pros:

• Change the destination without reprinting
• Track scan counts, locations, devices

Cons:

• Depends on the redirect service staying online (if they go down or shut down, your QR code breaks)
• The service sees every scan (privacy concern)
• Usually requires a paid subscription
• Slower — adds a redirect hop

Recommendation: Use static QR codes for permanent content (business cards, product packaging, signage). Only use dynamic QR codes when you specifically need to change destinations after printing AND you are comfortable with the privacy trade-off.

PureXio generates static QR codes exclusively — they work forever with no third-party dependency.

Practical Use Cases

Business Cards

Embed your vCard (contact information) in a QR code on your business card. When scanned, the recipient's phone automatically offers to save your name, phone, email, and company — no manual typing needed.

WiFi Sharing

Create a QR code that stores your WiFi network name, password, and encryption type. Guests scan it and connect instantly without asking for or typing the password. Popular for:

• Restaurant and cafe guest networks
• Airbnb and hotel room WiFi
• Office visitor networks
• Home networks for guests

Marketing and Print

Add QR codes to:

• Flyers and posters → link to your website or landing page
• Product packaging → link to instructions, warranty registration, or recipes
• Restaurant menus → link to online ordering
• Event tickets → encode ticket data for faster check-in
• Invoices → encode payment information (IBAN, amount, reference)

Payments

Many payment systems use QR codes. In Europe, the EPC QR code standard encodes IBAN, amount, and payment reference for instant bank transfers. In Asia, Alipay and WeChat Pay use QR codes as the primary payment interface.

Inventory and Logistics

Encode product IDs, batch numbers, or tracking URLs. QR codes hold more data than traditional barcodes and can be scanned with any smartphone — no special hardware needed.

Size and Print Guidelines

Minimum Print Size

The most common mistake with printed QR codes is making them too small. Follow these guidelines:

For close-range scanning (business cards, product labels): Minimum 2 x 2 cm (0.8 x 0.8 inches). This ensures reliable scanning from 10–20 cm distance.

For medium-range scanning (flyers, menus): Minimum 3 x 3 cm.

For distance scanning (posters, banners): Use this formula: QR code size = scanning distance / 10. A poster viewed from 2 meters needs a QR code at least 20 x 20 cm.

The 10:1 Rule

A common rule of thumb: the QR code should be 1/10th of the expected scanning distance. If someone will scan from 1 meter away, the code should be at least 10 cm on each side.

Print Resolution

Export your QR code at the highest resolution the generator offers. For print, aim for at least 300 DPI at the final print size. A 3 cm QR code at 300 DPI needs to be at least 354 x 354 pixels at export. PureXio lets you set the output resolution up to 2048 pixels for high-quality print use.

Contrast Requirements

QR codes need strong contrast between the dark modules and the light background. Black on white provides the best scan reliability. Avoid:

• Light-colored codes on medium backgrounds (gray on beige)
• Codes printed over busy photographic backgrounds
• Very thin module sizes relative to the contrast ratio

Customization Options

Colors

You can change the foreground and background colors, but maintain a minimum contrast ratio of 4:1. Dark foreground on light background is standard. Inverted (light on dark) works but scans less reliably with some older camera apps.

Logos and Branding

You can place a small logo in the center of the QR code if you use error correction level H (30% recovery). The logo should cover no more than 10–15% of the total code area. Go above this and the code becomes unscannable.

Shapes and Rounded Corners

Some generators offer rounded module corners or different module shapes (dots, rounded squares). These are purely aesthetic — the scanner still reads the underlying grid pattern. Use subtle modifications and always test the result.

Creating QR Codes: Step by Step

1. Choose the content type. URL, text, WiFi credentials, vCard, email, phone number, or SMS.

2. Enter the data. For URLs, include the full https:// prefix. For WiFi, enter SSID, password, and encryption type.

3. Set size and error correction. For print, use high resolution. For screen display, standard resolution is fine. If you plan to add a logo, select H error correction.

4. Generate and download. Export as PNG for web use or SVG for print (scales to any size without quality loss).

5. Test before deploying. Scan with at least 2 different phones (iOS and Android) at the expected viewing distance before printing.

Common Mistakes

Linking to a non-mobile-friendly page. QR codes are scanned with phones. If the destination is not responsive, users will leave immediately.

Not testing after printing. Colors shift in print. What looks high-contrast on screen may be low-contrast on paper. Always scan a printed proof.

Making them too small. See the size guidelines above. When in doubt, go bigger.

Using dynamic QR codes for permanent applications. If the redirect service shuts down, your printed QR codes become useless. For anything printed permanently (product packaging, signage, business cards), use static codes.

Encoding too much data. More data means a denser (more complex) pattern, which requires a larger print size for reliable scanning. Keep URLs short. Use URL shorteners if needed, but be aware this adds a dependency.

QR Codes vs. Barcodes

Traditional barcodes (UPC, EAN, Code 128) store data in one dimension — a series of vertical lines. QR codes store data in two dimensions — a grid of squares. This gives QR codes several advantages:

• More capacity: QR codes store up to 7,089 characters; standard barcodes store 20–25.
• Error correction: QR codes can be damaged and still scan. Barcodes cannot.
• Orientation independence: QR codes scan at any angle. Barcodes must be aligned horizontally.
• No special hardware: Any smartphone camera reads QR codes. Barcodes often need dedicated scanners.

For inventory and retail, both have their place. Barcodes are faster to scan in high-throughput environments (supermarket checkout lines). QR codes are more versatile for consumer-facing applications.

Privacy Considerations

Many free QR code generators are actually tracking services. They create dynamic QR codes that route through their servers, allowing them to:

• Log every scan (timestamp, location, device)
• Build profiles of who scans your codes
• Sell aggregate data to advertisers
• Display interstitial ads before redirecting

If you are creating QR codes for business use, this means a third party has detailed analytics about your customers' behavior — and you may not even realize it.

Static QR code generators like PureXio create codes that point directly to your destination. There is no intermediary, no tracking, and no data collection. The QR code is just encoded data — as simple as printing text on paper.

Frequently Asked Questions

Do QR codes expire?

Static QR codes never expire. They are just encoded data — like text printed on paper. They work as long as the encoded content (URL, WiFi network) is valid. Dynamic QR codes expire when the redirect service discontinues.

Can QR codes be malicious?

A QR code itself is just data. But the data can be a malicious URL (phishing site, malware download). Treat scanning an unknown QR code like clicking an unknown link — check the URL before opening it. Most phone cameras show a preview of the URL before opening.

What is the maximum data a QR code can store?

4,296 alphanumeric characters at error correction level L. For practical purposes, keep content under 300 characters for reliable scanning at moderate sizes.

Summary

QR codes are a mature, reliable technology with clear best practices: use static codes for permanence and privacy, size them appropriately for the scanning distance, maintain high contrast, and always test before deploying. A browser-based generator gives you full control with no tracking overhead.