What is a QR code and how does it work?
QR stands for Quick Response. A QR code is a two-dimensional barcode that stores data — most commonly a URL — in a grid of black and white squares. A phone camera reads the pattern and decodes the stored information, typically opening a website, dialling a number, or connecting to Wi-Fi.
QR codes were invented in 1994 by Denso Wave, a Japanese automotive company, to track vehicle parts during manufacturing. The design was intentionally made freely available rather than patented, which is why QR codes became a universal standard without licensing fees. Since smartphone cameras began natively reading QR codes around 2017–2018, usage has grown dramatically — on business cards, restaurant menus, product packaging, payment systems, and event tickets.
What can a QR code contain?
Most people think of QR codes as website links, but they can encode several types of data:
- URL — the most common use. Encodes a website address that opens in the phone's browser on scan.
- Plain text — displays a message on screen when scanned. Useful for displaying information without requiring internet access.
- Email — encodes an email address, subject line, and optional body text. Scanning opens the phone's mail app with fields pre-filled.
- Phone number — encodes a tel: link that dials the number directly when scanned. Common on business cards.
- SMS — encodes a phone number and pre-written message. Scanning opens the messaging app ready to send.
- Wi-Fi — encodes network name, password, and security type. Scanning connects the phone to the network without typing the password — very useful for cafes, offices, and events.
- vCard — encodes full contact details (name, phone, email, address) in a format phones can import directly to contacts.
How to create a QR code free — step by step
- Open the QR Code Generator at toolbase.work/pages/qr-code-generator.html
- Select the content type — URL, Text, Email, Phone, SMS, or Wi-Fi using the tabs at the top
- Enter your content — paste a URL, type your text, or fill in the relevant fields
- Customise the appearance — change foreground and background colors, select a dot style, and optionally upload a logo
- Click Generate QR Code — the preview updates in real time
- Download PNG — save a 1000 × 1000 pixel QR code ready for print or digital use
No sign-up is required and the downloaded file has no watermark. The QR code is generated entirely in your browser — nothing is transmitted to any server.
Create your QR code now — free
Custom colors, logo upload, 6 content types, PNG download. No sign-up, no watermark.
How to add a logo to a QR code
Adding a logo makes a QR code immediately recognisable as belonging to a brand. It works because of a built-in feature called error correction — QR codes contain redundant data throughout the pattern, so even if part of the code is damaged or covered, the scanner can reconstruct the missing data.
The four error correction levels and what they allow:
| Level | Coverage allowed | Best for |
|---|---|---|
| L — Low | Up to 7% damaged | Simple codes, clean environments |
| M — Medium | Up to 15% damaged | General use, slight wear expected |
| Q — High | Up to 25% damaged | Industrial, outdoor, small logos |
| H — Maximum | Up to 30% damaged | Logos, heavy branding, outdoor |
For any QR code with a logo: set error correction to H first, then upload your logo, and keep it under 25% of the total QR area. Test scan before printing — if it fails, reduce the logo size or switch to a shorter URL.
Logo format tips: PNG with a transparent background looks cleanest. Square logos (1:1 aspect ratio) centre better than wide or tall ones. Logos with fine detail or thin lines may not render well at small sizes — a simplified version often works better.
Choosing colors for a scannable QR code
Color choice is the most common reason custom QR codes fail to scan. The fundamental requirement is contrast — the scanner needs to distinguish dark modules from light background. Guidelines:
- Dark foreground on light background always works. Black on white is the most reliable combination. Dark navy, deep green, or dark brown on white or light grey all scan reliably.
- Light foreground on dark background works on modern phones. White dots on black or dark navy background scan well on iPhone and most Android devices, though some older barcode scanners may struggle.
- Avoid low contrast. Light yellow on white, medium grey on light grey, or any combination where the dots don't clearly stand out will cause scanning failures.
- Test across devices. A color combination that looks fine on your screen may have lower contrast when printed on matte paper. Always test on both iPhone and Android before committing to a print run.
- Avoid colorful backgrounds. A background with patterns, gradients, or images behind the QR code creates interference. Keep the background a solid, uniform color.
QR code dot styles — what the options mean
The dot style changes the shape of the individual modules (the small squares) that make up the QR pattern:
- Square — the classic QR look. Maximum compatibility with all scanners including older devices and dedicated QR scanner hardware.
- Rounded — square modules with rounded corners. Softer appearance, still highly compatible.
- Dots — circular modules. More visually distinctive, compatible with all smartphone cameras.
- Classy — mixed shapes creating a more decorative appearance. Compatible with modern smartphone cameras.
The corner squares (the three large squares in the corners) can also be styled separately. Square corners look traditional; rounded or circular corners give a more modern, branded look. Corner style has no effect on scanning reliability.
What size to print a QR code
Too small and the camera struggles to resolve the pattern. The minimum safe size depends on the content — a short URL produces fewer modules (a simpler pattern) and can be printed smaller than a long URL or complex data.
| Where used | Minimum | Recommended |
|---|---|---|
| Business card | 1.5 × 1.5 cm | 2.5 × 2.5 cm |
| Flyer or brochure | 2 × 2 cm | 4 × 4 cm |
| A4 poster | 3 × 3 cm | 6 × 6 cm |
| Large banner | 10 × 10 cm | 20 × 20 cm or larger |
| Outdoor signage (2m+ viewing distance) | 20 × 20 cm | 40 × 40 cm |
The 1000 × 1000 pixel PNG from the ToolBase generator prints cleanly up to A4 at 150 DPI. For large-format printing (banners, signage), ask your printer to scale using nearest-neighbor interpolation, which keeps the QR edges sharp rather than blurring them.
Why isn't my QR code scanning? Common problems
| Problem | Likely cause | Fix |
|---|---|---|
| Code doesn't scan at all | Too small, low contrast, or very long URL | Print larger, increase contrast, shorten URL with a link shortener |
| Scans but goes to wrong URL | Typo in the original URL | Double check the URL before generating; test scan on screen first |
| Logo version doesn't scan | Logo too large, EC level too low | Set EC to H, reduce logo size to under 20% |
| Only scans in bright light | Low contrast color choice | Increase contrast between dots and background |
| Works on iPhone but not Android | Light-on-dark colors (some Android scanners) | Switch to dark-on-light or test specific devices used by your audience |
| Code scans in app but not camera | Camera QR detection disabled | User needs to enable "Scan QR codes" in camera settings |
QR codes in Pakistan — common uses
QR code adoption in Pakistan has accelerated through Raast and other digital payment systems. Several practical uses specific to the Pakistani context:
- Payment QR codes — JazzCash, EasyPaisa, and bank apps generate their own payment QR codes. Businesses display static QR codes at the counter for customers to scan and pay.
- Business card QR codes — encoding a vCard or professional website URL on a business card means contacts can save your details in one scan.
- Restaurant menus — post-pandemic, many Pakistani restaurants switched to QR code menus. A URL QR code links to a PDF or webpage of the current menu.
- Event tickets — university events, exhibitions, and conferences increasingly use QR codes on digital tickets for entry verification.
- Product authentication — some brands use QR codes on packaging linking to product verification pages to combat counterfeiting.
Static vs dynamic QR codes
QR codes generated by this tool are static — the data is encoded directly in the pattern. Once generated, the content cannot be changed. The code never expires and works forever as long as the destination (for URLs) remains live.
Dynamic QR codes (offered by paid services like QR Tiger, QRfy, Bitly) use a redirect URL — the QR code actually encodes a short tracking URL, and that URL redirects to the final destination. This allows you to change the destination without printing a new QR code, and track how many times the code has been scanned. These services typically charge a monthly fee.
For most use cases — business cards, posters, menus, Wi-Fi codes, contact details — a static QR code is perfectly adequate and costs nothing. Use dynamic QR codes only if you specifically need to change the destination after printing or require scan analytics.