QR Codes Explained: How They Work, How to Create Them and When to Use Them

Technology · 2026-06-08

QR codes went from a niche industrial tool to something you see on every restaurant table, business card and event poster. The pandemic accelerated their adoption, but they have stuck around because they genuinely solve a problem: getting information from the physical world into a digital device instantly.

How QR Codes Actually Work

A QR (Quick Response) code is a two-dimensional barcode that stores data in a grid of black and white squares. Unlike traditional barcodes that store data in one direction (horizontally), QR codes store data both horizontally and vertically, which allows them to hold much more information.

The three large squares in the corners are position markers — they help your phone's camera figure out the orientation and angle of the code. The smaller patterns handle alignment and timing. The remaining squares encode the actual data using a system called Reed-Solomon error correction, which means the code still works even if part of it is damaged or obscured. Depending on the error correction level, up to 30% of the code can be missing and it will still scan successfully.

A standard QR code can store up to about 3,000 characters of text, though in practice most codes contain far less — typically a URL of 50-100 characters.

What You Can Store in a QR Code

The most common use is encoding a URL — scan the code and your phone opens a website. But QR codes can store several types of data.

URLs — the most common use. Link to a website, a specific product page, a menu, a booking form or a social media profile. Plain text — any text string up to the character limit. Useful for short messages, instructions or reference numbers. Wi-Fi credentials — encode your network name, password and security type so guests can connect by scanning. No more spelling out complicated passwords. Contact information (vCards) — encode your name, phone number, email and address. When someone scans it, their phone offers to save you as a contact. More reliable than exchanging business cards. Email addresses — scan to open a pre-filled email with a specific recipient, subject line and even body text. Calendar events — encode an event with date, time, location and description. Scanning adds it directly to the recipient's calendar. Geographic coordinates — link to a specific location on a map. Useful for event venues, meeting points or business locations.

Practical Uses

For Business

Restaurants use QR codes for digital menus, eliminating printing costs and making updates instant. Retail shops link to product reviews and detailed specifications. Estate agents put codes on property signs linking to virtual tours. Service businesses link to booking pages, cutting out the friction of customers having to find and navigate a website.

For Events

Concert and event tickets are increasingly QR-based — harder to counterfeit than printed tickets and easier to validate at the door. Conference organisers put codes on name badges linking to attendees' LinkedIn profiles. Speakers include codes in presentation slides linking to resources and references.

For Personal Use

Share your Wi-Fi password with guests without dictating it character by character. Put a code on lost items (luggage, pet collars, key rings) linking to your contact details. Create codes for your social media profiles to share at networking events.

For Marketing

QR codes on print materials (flyers, posters, packaging) bridge the gap between offline and online. The key advantage over printing a URL is that codes are easier to scan than URLs are to type, especially on mobile. A code on a poster converts far better than a URL printed in small text.

Best Practices for QR Codes

Size matters. A QR code needs to be large enough to scan reliably. The general rule is that the scanning distance is roughly 10 times the code width. A 2cm code works at about 20cm (holding your phone close). A code on a billboard needs to be much larger. Contrast is essential. Dark modules on a light background works best. Black on white is the most reliable combination. Avoid low-contrast colour combinations — light grey on white or dark blue on black will fail to scan. Test before printing. Always scan your code with multiple devices before committing to print. Different phones and QR reader apps handle edge cases differently. Keep the URL short. Longer data means a denser code with smaller modules, which is harder to scan at distance. Use short URLs where possible. Add a call to action. A QR code on its own tells people nothing. Add text like "Scan for menu", "Scan to connect to Wi-Fi" or "Scan for tickets". People need a reason to point their camera at a square.

Static vs Dynamic QR Codes

A static QR code has the data baked in permanently. Once generated, it cannot be changed. If you encode a URL and later want to change where it points, you need to generate and print a new code.

A dynamic QR code encodes a short redirect URL. The redirect destination can be changed at any time without reprinting the code. This is useful for marketing materials where you might want to update the landing page, or for menus that change seasonally. Dynamic codes typically require a paid service.

For most personal and small business uses, static codes pointing to stable URLs are perfectly fine and completely free to generate.

Our free QR Code Generator creates high-quality codes instantly in your browser. Enter any text, URL, Wi-Fi credentials or contact details and download the result as a PNG image. Everything is processed locally — your data never leaves your device.