⌘ K
base62 · 0-9 A-Z a-z · encode · live

Encode & decode Base62

Compact, URL-safe encoding using digits plus upper- and lower-case letters. Common for short URLs, analytics IDs, and tokenised primary keys.

Base62 Converter
Input
32 B
1 lines
Output
43 B
1 lines
Status
ready
live
Ratio
1.34×
out/in
input · text
output · base62
OlhrHnj0RPPAUenyG9SuhoKJZNTg1B07SoFeMcJ8Bgj
Quick Start

How to convert Base62

Base62 keeps URLs free of escaping (0-9 A-Z a-z). About 17% shorter than Base36 thanks to the case-sensitive alphabet.

  1. 01

    Pick mode

    Encode bytes to Base62 or decode Base62 back to 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 input

    Any UTF-8 text — emoji and accents survive intact.

    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
    /orders/47185
    options applied · livelive
  3. 03

    Live convert

    BigInt-based, so arbitrarily long inputs encode exactly.

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

    livememoisedoptionsinstantreactive
    out · encodedb62 · ready
    AAwf93rvy4aWQVw
    encoded · livelossless
  4. 04

    Copy or download

    Drop straight into URLs or database columns.

    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 toolsBase58 ConverterBase36 ConverterBase32 ConverterBase64 EncoderHashids ConverterNanoID Generator
Use Cases

When to use Base62

Short URLs, analytics IDs, token formats.

Short URLs

youtu.be/dQw4w9WgXcQ — 7 chars covers 3.5T values. 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

Analytics IDs

GA4 client IDs, Mixpanel distinct IDs. 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

Token formats

Compact session IDs and CSRF tokens. 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

DB primary keys

Obfuscate sequential ids without losing reversibility. 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

Tracking pixels

Stuff metadata into a tight querystring. 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

URL-safe

No /, +, or = — never needs URL encoding. 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

Base64 needs +, /, = which require URL escaping. Base62 drops them entirely for slightly longer but always-URL-safe output.
Base62 of N bytes varies in length. For fixed-length IDs prefix or pad yourself after encoding.
Yes — A and a are different. That's how it stays 17% denser than Base36.
Yes. BigInt math means no precision loss regardless of input size.
No — encoding and decoding happen locally in your browser.
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