65 symbols · arbitrary precision

Base65 converter

A non-standard encoding built for this page: input bytes are read as one large integer and re-expressed in base 65. Type below — the strip lights up the symbols your data actually uses.

0 chars
encodes to
or decode
0 chars

How to use this tool

  1. Type or paste text into the Text → Base65 box — the encoding appears instantly in Base65 output.
  2. Click Copy result to grab the string.
  3. To decode, paste a Base65 string into Base65 → Text and the plain text appears below.
  4. The symbol ribbon lights up to show which of the 65 characters your data uses.
  5. Use Clear any time to reset a box.

Why this tool is helpful

Explore arbitrary bases

A hands-on way to see how any byte stream can be re-expressed in an unusual base using arbitrary-precision math.

Understand BigInt conversion

Watch a whole byte sequence be treated as one huge integer and divided down into base-65 digits.

Learn how encodings are built

See the exact pattern behind Base36/58/62 — same idea, different alphabet and base.

Experiment safely

Because it is non-standard, you can play without worrying about breaking real-world formats.

Stay private

Everything runs in your browser. Nothing is uploaded, logged, or sent to a server.

FAQ

What exactly is Base65?

A custom, non-standard 65-symbol encoding built for this page: input bytes are read as one large integer and re-expressed in base 65.

What alphabet does it use?

0–9 A–Z a–z + - . — 65 symbols total.

Is Base65 a standard I can rely on?

No. It is an educational/research tool, so its output will not interoperate with other "Base65" tools (they may use different alphabets).

Why 65 symbols?

Just above Base64 — a teaching example showing the same conversion technique generalized to any base.

Does it use padding?

There is no = padding; the 0 character is reused to preserve leading zero bytes.

Does any of my data leave my browser?

Never. All conversion happens locally in JavaScript.