Best Free QR Code Generator & Scanner

Quickly and simply scan or create QR codes for your projects and download them in vectorial SVG files or in lossless PNG images, 100% free and without redirects or tracking codes.

1. What Is a QR Code? (TL;DR)

A QR code (Quick Response code) is a two-dimensional barcode made of black and white squares (“modules”) on a grid. It can store text, URLs, binary data, or structured payloads and be scanned rapidly from multiple angles by cameras. Compared with 1D barcodes, QR codes hold more data, are orientation-independent, and include robust error correction.

2. A Short History & Timeline

  • 1992–1993: Denso engineers explore 2D codes for automotive part tracking.
  • 1994: Denso Wave officially invents the QR Code; speed and robustness are key goals.
  • 1997: First public spec in Japan (JIS X 0510).
  • 2000: International standardization via ISO/IEC 18004.
  • 2004–2010: Mobile phones and data networks drive adoption in Asia.
  • 2010s: Global use for marketing, payments, and authentication.
  • 2020–2022: COVID-19 accelerates mainstream, contactless usage worldwide.
  • Today: Ubiquitous across industries, with open/royalty-free implementation.

3. Anatomy of a QR Code

Standard (Model 2) QR codes contain predictable structural elements:

  • Finder Patterns (×3): Large squares at three corners for detection & orientation.
  • Separators: White modules around finders.
  • Timing Patterns: Alternating modules to determine grid spacing.
  • Alignment Patterns: Smaller targets used for distortion correction (versions ≥ 2).
  • Format Information: 15 bits storing EC level and mask pattern (with BCH protection).
  • Version Information: 18 bits (versions ≥ 7) encoding the version number (also BCH-protected).
  • Data & Error Correction Codewords: The payload and parity bytes.
  • Quiet Zone: 4-module white margin around the symbol.

4. How Encoding Works: From Text to Modules

  1. Choose the smallest version (size) that fits data + chosen EC level.
  2. Select a data mode (numeric, alphanumeric, byte, Kanji, ECI).
  3. Create a bit stream: mode indicator → character count → encoded data.
  4. Add terminator bits and pad to full codewords.
  5. Generate Reed–Solomon parity codewords.
  6. Interleave data & EC codewords per spec.
  7. Place bits in the matrix in a zig-zag traversal.
  8. Try all 8 masks, score, and pick the best.
  9. Insert format & version info bits.

4.1 Choosing the Mode

  • Numeric: digits 0–9; ultra-compact (10 bits per 3 digits).
  • Alphanumeric: 45-char set (0–9, A–Z, space, $%*+-./:); 11 bits per 2 chars.
  • Byte: 8-bit bytes (UTF‑8 or arbitrary binary).
  • Kanji: Shift JIS mapping for common Japanese characters.
  • ECI: Extended Channel Interpretation for non-default encodings.

Encoders can switch modes mid-stream to save space.

4.2 Character Count Indicator

The bit-length varies by mode and version range (1–9, 10–26, 27–40). Example: numeric uses 10/12/14 bits respectively.

4.3 Converting to Data Codewords

Bits are grouped into 8-bit codewords. Add terminator bits (≤4 zeros), then pad with 0xEC and 0x11 alternately until full.

4.4 Error Correction with Reed–Solomon Codes

  1. Treat data codewords as polynomial coefficients.
  2. Divide by a generator polynomial to get parity bytes.
  3. Append parity to form each block’s full codeword set.

EC level determines parity amount:

  • L (~7% recovery)
  • M (~15%)
  • Q (~25%)
  • H (~30%)

4.5 Interleaving & Final Structure

Data is split into groups/blocks, RS-applied separately, then bytes are interleaved to spread risk of localized damage.

4.6 Masking & Penalty Scores

Eight logical masks are tested to minimize patterns that hinder decoding. Penalties are given for long runs, 2×2 blocks, finder-like patterns, and poor dark/light balance.

4.7 Format & Version Information

  • Format Info: 5 bits (EC level) + 3 bits (mask) encoded with BCH (15,5).
  • Version Info: For versions ≥7: 6 bits version + 12 bits BCH.

5. Decoding Pipeline: How Scanners Read Them

  1. Locate finder patterns via image processing.
  2. Determine orientation & perspective using the finders.
  3. Sample the grid using timing patterns.
  4. Read format info → get mask & EC level.
  5. Unmask the data area.
  6. Extract codewords by zig-zag traversal.
  7. Split into blocks and run Reed–Solomon decoding.
  8. Concatenate data codewords, parse mode/length/payload.
  9. Reconstruct original text/binary per mode rules.

6. Versions, Sizes, and Capacities

Version numbers range from 1–40. The number of modules per side is:

modules = 21 + 4 × (version − 1)
  • Version 1 → 21×21 modules
  • Version 40 → 177×177 modules

Approximate maximum capacities at Version 40 / Level L:

  • Numeric: ~7,089 digits
  • Alphanumeric: ~4,296 characters
  • Binary (8-bit): ~2,953 bytes
  • Kanji: ~1,817 characters

Most consumer codes use Versions 1–10 (≤57×57).

7. Error Correction Levels (L, M, Q, H)

Level Recovery Capacity* Typical Use Cases
L ~7% Clean printing, plenty of space
M ~15% General-purpose marketing
Q ~25% Likely wear/overprint
H ~30% Logos in codes, harsh environments

*Approximate percentage of codewords that can be restored. Higher EC means fewer data bytes and larger versions.

8. Variants & Related Standards

  • Model 1 vs. Model 2: Model 2 is prevalent; adds capacity and alignment patterns.
  • Micro QR: Tiny (M1–M4) for very small items; only one finder pattern.
  • iQR Code (Denso Wave): Rectangular options, higher capacities, 3–30% EC.
  • FrameQR: Decorative frames with logos/pictures.
  • SQRC: “Secure QR Code” with encrypted segments.
  • JIS X 0510: Japanese standard.
  • ISO/IEC 18004: International specification (revisions in 2015, 2024).
  • Alternatives: Data Matrix, Aztec, PDF417, MaxiCode, etc.

9. Common & Creative Uses

  1. URLs & Marketing: Bridge print to web; track with UTM parameters.
  2. Payments & FinTech: Alipay, Paytm, PIX (Brazil), UPI (India), SEPA QR (EU).
  3. Authentication & 2FA: TOTP provisioning, device login handshakes.
  4. Logistics & Manufacturing: Traceability, parts tracking, warranty labels.
  5. Tickets & Boarding Passes: Offline validation at gates.
  6. Wi‑Fi Sharing: SSID + password embedding.
  7. Crypto & Wallets: Payment requests and addresses.
  8. Digital Menus & Forms: Contactless ordering/check-ins.
  9. AR/VR & IoT: Onboarding devices, context triggers.
  10. Education & Museums: Link to multimedia or extended info.
  11. Healthcare: Samples, patient IDs, e-prescriptions.
  12. Smart Packaging: Nutrition, provenance, recycling info.
  13. Government & Public Health: Check-ins, certificates, tax invoices.

10. Designing Better QR Experiences

  • Provide context: e.g., “Scan to …”.
  • Include a short URL fallback for non-camera users.
  • Mind contrast & size: High contrast; ~1″ (2.5 cm) minimum for print. Rule: size ≈ scan distance / 10.
  • Quiet zone: Leave ≥4 modules of white space.
  • Test broadly: Different devices, lighting, print materials.
  • Avoid busy backgrounds and low-contrast colors.
  • Dynamic vs. static: Use dynamic if you need analytics or redirection later.
  • Accessibility: Provide alt text and non-QR alternatives.

11. Security, Privacy & Risks

  • Phishing & Malware: Hidden malicious URLs.
  • QRjacking / Quishing: Attackers overlay fake codes on real posters.
  • Data Harvesting: Tracking parameters log user info.
  • Plaintext Secrets: Printed Wi‑Fi passwords or API keys can be scraped.
  • Mitigations: Verify domains, educate users, sign payloads (JWS), expire sensitive data.

12. FAQs

The core QR specifications were released royalty-free by Denso Wave. Implementing ISO/IEC 18004 does not require fees. Branded variants (iQR, FrameQR) may have licensing.

Up to ~7,089 numeric digits or ~2,953 bytes at Version 40 / Level L. Real-world codes are usually smaller.

Yes, but you should keep high contrast (dark foreground, light background). Avoid inversions unless the scanner supports them, some old phones/devices can't detect light on dark QR codes.

No... While some tools offer it and it sounds cool and edgy at first, changing the square edges to triangles, rounded borders, circles or other non-standard shapes will make the QR code less legible, prone to readability errors and user frustration or loss of sales. To avoid such problems, this tool discourages this type of customization.

Reed–Solomon error correction can restore data up to the selected EC level’s capacity.

Static codes do not. Dynamic codes can be disabled or redirected by the service provider.

Depends on scanner & distance. ~1–1.5 cm micro QR for close-up, ~2.5–3 cm for posters.

Yes. Use byte mode (UTF‑8) or ECI to specify character sets.

Likely a typo, redirect issue, or malicious sticker overlay.

They’re just carriers; security relies on cryptographic protocols and trusted apps verifying servers.

Both are 2D codes. Data Matrix excels in tiny markings (e.g., pharma); QR is widely recognized and phone-friendly.

Yes, use higher EC (Q/H) and test thoroughly.

Eight is a practical compromise; testing all is cheap and improves readability.

SVG or high-res PNG for print; PNG/SVG for web. Avoid JPEG (blurry edges).

Use deep links / app links (URI schemes, Android App Links, iOS Universal Links) with fallbacks.

Yes: encrypt first, then encode. QR itself doesn’t provide encryption; you manage keys separately.

Finder & alignment patterns correct skew within limits; extreme angles or glare still hurt.

No hard limit beyond version 40. Physical size can be huge (e.g., rooftops) if modules stay proportional.

EU DCC, SMART Health Cards (JWS/Base45), etc.—they define their own payloads on top of QR.

Likely glare, moiré, or contrast issues. Increase brightness/size.

The code itself cannot, but the URL can log IP, device, time—treat it like any web link.

13. Glossary

Module
A single black/white square in the QR grid.
Version
Determines dimensions (modules per side).
Codeword
8-bit chunk of data or error correction bytes.
Mask Pattern
Binary pattern XOR’d with data modules to reduce visual artifacts.
BCH Code
Error-correcting code used for format/version info.
Reed–Solomon
Finite-field error correction used for data area.
Quiet Zone
White-space margin around the code.
ECI
Extended Channel Interpretation (character set info).

14. Further Reading & Standards Numbers

  • ISO/IEC 18004: International QR Code standard.
  • JIS X 0510: Japanese Industrial Standard for QR.
  • Denso Wave’s official site & technical guides.
  • Reed–Solomon & BCH academic papers for deeper math.
  • Open-source libs: ZXing, ZBar, qrcode.js, pyqrcode, qrencode.

15. Appendix A: Pseudocode for a Minimal Encoder

function encode_qr(data, ec_level):
    mode = choose_mode(data)
    version = smallest_version_that_fits(data, mode, ec_level)
    bitstream = []
    bitstream.append(mode_indicator(mode))
    bitstream.append(char_count_indicator(len(data), mode, version))
    bitstream.append(encode_data_bits(data, mode))
    bitstream = pad_to_codewords(bitstream, version, ec_level)

    blocks = split_into_blocks(bitstream, version, ec_level)
    for block in blocks:
        block.ec = reed_solomon(block.data)
    interleaved = interleave(blocks)

    matrix = place_bits(interleaved, version)

    best_mask = argmin(mask_patterns, penalty_score(mask(matrix)))
    matrix = apply_mask(matrix, best_mask)

    insert_format_info(matrix, ec_level, best_mask)
    if version >= 7:
        insert_version_info(matrix, version)

    return matrix

16. Appendix B: Mask Pattern Formulas

Let r = row index, c = column index (0-based). Data modules are XOR’d with 1 if the expression is true.

  1. (r + c) mod 2 == 0
  2. r mod 2 == 0
  3. c mod 3 == 0
  4. (r + c) mod 3 == 0
  5. ((r div 2) + (c div 3)) mod 2 == 0
  6. ((r * c) mod 2) + ((r * c) mod 3) == 0
  7. (((r * c) mod 2) + ((r * c) mod 3)) mod 2 == 0
  8. (((r + c) mod 2) + ((r * c) mod 3)) mod 2 == 0

Penalty rules score:

  • Runs of ≥5 same-colored modules
  • 2×2 blocks of same color
  • Finder-like 1:1:3:1:1 patterns
  • Overall dark/light balance (target ~50%)

16. Developer API

text

You can pass a ?text= GET parameter to automagtically load a text string in the tool.

full

Passing a &full parameter will show the QR in full screen

qrStrokeColor / qrBgColor

Stroke and background colors of the QR code in hexadecimal, without the # symbol. Example: ff0000