QR Code Generator

About QR Code Generator

A QR code (Quick Response code) is a two-dimensional barcode that can store various types of information. This tool allows you to create custom QR codes for URLs, text, WiFi credentials, contact information, and more with extensive customization options.

Are QR codes free to use commercially, or do I need a license?

QR codes themselves are completely free for any use — commercial, personal, educational, or governmental. Denso Wave invented QR codes in 1994 and patented the technology, but chose not to enforce the patent, instead publishing the specification as an open standard (ISO/IEC 18004). This means anyone can generate, scan, print, or distribute QR codes without paying royalties. However, the QR Code trademark is registered by Denso Wave in some countries, so commercial products explicitly marketed as containing "QR Code" technology should ideally credit "QR Code is a registered trademark of DENSO WAVE INCORPORATED." This tool generates plain QR codes you can use freely on business cards, packaging, signage, ads, menus, and merchandise without any licensing concerns.

What error correction level should I choose: L, M, Q, or H?

QR codes support four Reed-Solomon error correction levels: L (low, ~7% recoverable), M (medium, ~15%), Q (quartile, ~25%), and H (high, ~30%). Higher levels add redundancy bytes that let scanners reconstruct data even when the code is partially damaged, scratched, or obscured by a logo. Use L for clean digital displays where the code is never damaged. Use M (the most common default) for general printing and screen display. Use Q for outdoor signage exposed to dirt, sun fade, or partial occlusion. Use H when you embed a logo in the center of the QR code — the logo physically obscures modules, and only H tolerates that loss reliably. Higher correction increases module count, making the code denser, so balance robustness against scannability at small print sizes.

Why does my QR code look different from another generator's even with the same content?

Two QR codes encoding identical data can look completely different because of three independent variables: version (size, from 1 = 21x21 modules to 40 = 177x177), error correction level (L/M/Q/H adds different amounts of redundancy), and data mask pattern (0-7, chosen automatically to minimize visual artifacts that confuse scanners). Different generators may pick different combinations even for the same input. Additionally, encoding mode matters — numeric mode packs 3 digits into 10 bits, alphanumeric mode packs 2 chars into 11 bits, and byte mode uses 8 bits per UTF-8 byte — so a URL with mixed case lands in byte mode while uppercase letters and digits use the more efficient alphanumeric mode. All valid QR codes scan identically; visual differences are cosmetic.

How much data can a single QR code hold?

Maximum capacity depends on version, error correction level, and encoding mode. Version 40 (the largest, 177x177 modules) at error correction L holds: 7,089 numeric characters, 4,296 alphanumeric characters, 2,953 binary bytes, or 1,817 Kanji characters. At correction level H, those caps drop to about 3,057 numeric, 1,852 alphanumeric, 1,273 bytes, or 784 Kanji. In practice, QR codes over version 10 (57x57) become hard to scan with phone cameras at typical viewing distances — modules get too small. For URLs, keep the encoded string under 300 characters when possible; longer URLs force a denser code that requires a closer scan distance and a higher-resolution camera. Use URL shorteners for very long links rather than maxing out QR capacity.

Can QR codes contain viruses or harmful content?

A QR code itself is just encoded text — it cannot execute code, install software, or carry a virus. The danger is what scanners do with the text. The most common attack is phishing: a malicious QR code points to a fake login page that captures credentials, or to a drive-by-download URL serving malware to vulnerable browsers. Other payloads include WiFi join strings that connect you to a rogue access point, vCards with malicious phone numbers, calendar invites with tracking links, and SMS/email actions that send messages without an obvious confirmation. Always preview the decoded URL before tapping it — most modern phone cameras show the destination first. Avoid scanning QR codes from untrusted physical locations (parking meters, restaurant tables) where stickers may have been swapped — a 2024 FBI advisory specifically warned about QR-code overlay attacks.

What's the smallest size I can print a QR code and still have it scan reliably?

The rule of thumb is the 10:1 distance-to-size ratio: a QR code should be 1/10 the maximum expected scan distance. For a phone held at 30 cm reading a business card, 3 cm (about 1.2 inches) per side works for low-density codes. For billboards read from 10 meters away, you need 1 meter per side. Module size — not overall size — is what actually matters: each module should be at least 0.4 mm wide for print scanning and ideally 1 mm for casual phone scans. A version 5 QR code (37x37 modules) at 3 cm gives 0.81 mm per module, which scans well. Higher versions need either larger prints or higher-resolution cameras. Always include the quiet zone (4-module white border) — without it, even a perfect QR code fails to scan.

Can I customize the colors of a QR code and still have it scan?

Yes, but with constraints rooted in how scanners work. QR scanners detect light/dark contrast, so the foreground must be significantly darker than the background — typically at least 50% contrast in luminance. Dark blue, dark green, dark purple, and black on white or pastel backgrounds work reliably. Inverted codes (light foreground on dark background) often fail because the ISO standard expects dark-on-light; many scanners refuse to read inverted codes. Avoid red on green or other equiluminant color pairs that look distinct to the eye but appear nearly identical in grayscale. Gradients and photo backgrounds reduce scan reliability — test on multiple devices before printing. If you use a logo overlay, set error correction to H, keep the logo under 25% of total area, and centered to preserve the three position-detection squares in the corners.

What's the difference between static and dynamic QR codes, and which should I use?

A static QR code encodes the final destination directly into the modules — once printed, the content cannot change. A dynamic QR code encodes a short redirect URL pointing to a service that forwards to the real destination, which you can update server-side without reprinting. Static codes are free, work offline, never expire, and have no third-party dependency — ideal for personal use, vCards, WiFi credentials, and content you never need to update. Dynamic codes require a paid service in most cases, can break if the redirect provider shuts down, but give you analytics (scan counts, locations, times) and the ability to rotate destinations for A/B testing or campaign updates. This tool generates static codes. For marketing campaigns where you need to track scans or change destinations, use a dedicated dynamic QR service, but understand you're trusting that third party for the life of every printed code.

What QR version and minimum print size will my code need?

When you generate a code, this tool reports the real QR version (1-40) and the module grid it produced — not a vague "Auto." The version is driven by how much data you encode at your chosen error-correction level: a short URL might be version 2 (25x25 modules), while a long vCard at level H can jump to version 10+ (57x57) and beyond. That version dictates the minimum print size. The reliable floor is 0.4 mm per module, so a 33x33 (version 4) code plus a 4-module quiet zone on each side spans 41 modules — about 17 mm (0.65 in) minimum. The Scannability Pre-flight panel does this math for you and also applies the 10:1 distance rule: a code printed N mm wide scans reliably from up to about N centimetres away. If your code reports a high version, shorten the content (use a URL shortener), drop the error-correction level, or commit to a larger print size before sending the job to press.