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base45 · RFC 9285 · encode · live

Encode & decode Base45

RFC 9285 encoding tuned for QR codes — uses the 45-character alphanumeric set so payloads stay compact in QR alphanumeric mode.

Base45 Converter
Input
10 B
1 lines
Output
15 B
1 lines
Status
ready
live
Ratio
1.50×
out/in
input · text
output · base45
4692A6U%6:*8G7B
Quick Start

How to convert Base45

Base45 maps every 2 input bytes to 3 chars from the QR alphanumeric set. That makes scannable codes ~40% smaller than Base64 in alphanumeric mode.

  1. 01

    Pick mode

    Encode for QR generation; decode to recover the original bytes.

    Bytes flow through TextEncoder/TextDecoder for predictable UTF-8 semantics — emoji, surrogate pairs, and combining marks all encode losslessly.

    modeUTF-8TextEncoderlosslesslive
    mode · raw bytesencode · UTF-8
    encode · decode
    loaded · UTF-8MIME · ready
  2. 02

    Paste payload

    UTF-8 text or a Base45 string from a scanned QR.

    Hash and signature operations call crypto.subtle from the Web Crypto API, so output matches OpenSSL / Node bit-for-bit.

    utf8Web Cryptosubtledeterministiclive
    input · optionstext · live
    HC1:6BFOXN
    options applied · livelive
  3. 03

    Live convert

    Output updates as you type — no roundtrip to a server.

    Options re-run instantly through useEffect + useMemo — switching URL-safe mode or padding doesn’t re-encode from scratch.

    livememoisedoptionsinstantreactive
    out · encodedb45 · ready
    QED8WEX0
    encoded · livelossless
  4. 04

    Drop into QR

    Pair with the QR generator to print scannable badges.

    Copy uses the Async Clipboard API; downloads ship via Blob with the appropriate MIME (text/plain, image/png, …) so external tools recognise them.

    exportclipboardblobMIME-correctclient-side
    ✓ · copiedready · done
    ✓ Copied
    shipped · ready to shipsuccess
Pro tips

Encoding without surprises

Always UTF-8 first

Use TextEncoder / TextDecoder for bytes ↔ string conversion. btoa alone breaks on non-ASCII.

URL-safe vs standard Base64

Standard uses +, /, =; URL-safe swaps to -, _, no padding. Don’t mix them.

Hashes aren’t passwords

SHA-256 is fast; that’s good for fingerprints, bad for passwords. Use bcrypt / argon2 for credentials.

Watch padding rules

Some decoders are strict about = padding, others auto-pad. If round-trips fail at exactly 1 or 2 bytes, check padding.

Use Web Crypto for keys

Generate cryptographic keys via crypto.subtle, never Math.random. The latter is predictable.

JWT decode ≠ verify

Decoding a JWT just splits and base64-decodes. Verification needs the issuer’s public key / shared secret.

Related toolsBase32 ConverterBase58 ConverterBase64 EncoderBase85 ConverterQR Code GeneratorText to Hex
Use Cases

When to use Base45

QR codes, health passes, IoT diagnostics.

EU COVID DCC

Digital green certificates wrap CBOR in Base45. Output round-trips losslessly with the matching decoder — both run client-side, so end-to-end testing happens in a single tab. Encoding flows through TextEncoder for predictable UTF-8 semantics.

RFC-compliant

Boarding passes

IATA bar codes use the same alphanumeric set. Web Crypto's subtle.digest produces output that matches OpenSSL, GPG, and Node's crypto module byte-for-byte. That makes the result trustworthy as a content fingerprint, ETag, or integrity check.

OpenSSL-matched

Compact QR

Alphanumeric mode beats byte mode for ~10x packing. Pairs cleanly with HMAC, JWT, and signed-URL workflows where bit-level correctness matters. The browser's crypto stack is FIPS 140-validated in Chrome and Firefox, so it's production-grade.

lossless

Device pairing

Short codes printed on stickers for setup. Output uses canonical RFC 4648 / 7515 alphabets so curl, openssl, and any standards-compliant decoder accept it as input. URL-safe variants drop padding for tokens that travel in query strings.

byte-identical

Loyalty cards

Stash CBOR payloads under a phone-scannable code. Heavy hashing runs through useMemo so large inputs don't block typing. PBKDF2, bcrypt, and Argon2 expose configurable cost factors — tune for your threat model, not the default.

spec-grade

Cross-platform

RFC 9285 means consistent decoding everywhere. Same input plus same options always yields identical bytes. That's the foundation for content-addressed storage (IPFS, Git, S3 ETags) and means the output is safe to commit to fixtures.

production-ready
FAQ

Frequently asked questions

QR alphanumeric mode encodes pairs from a 45-glyph set into 11 bits, packing tighter than byte mode.
No. The alphabet is upper-case only; the decoder normalises lower-case input automatically.
Output is slightly longer (~67% vs 33% overhead) but fits a QR alphanumeric stream — net QR size shrinks.
EU Digital COVID Certificates prefix payloads with HC1:. Strip it before decoding the Base45 body.
No — the conversion runs locally in your browser.
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