91 symbols · basE91 · ~23% overhead · densest printable
The densest encoding that stays within safe printable ASCII (~23% overhead). Invented as "basE91," it squeezes more bits per character than any competing text-safe encoding. Less standardized than Base64 or Base85, but unbeatable for compactness in printable form.
Text → Base91 box — the basE91 encoding appears instantly in Base91 output.Copy result to grab the string.Base91 → Text and the plain text appears below.Clear any time to reset a box.The densest printable-ASCII encoding — about 23% overhead, smaller than Base64 or Base85.
When every byte counts, basE91 fits the same data into fewer characters.
Watch a streaming 13/14-bit packing algorithm work character by character.
Understand the trade-offs of pushing near the theoretical limit of printable ASCII.
Everything runs in your browser. Nothing is uploaded, logged, or sent to a server.
A binary-to-text encoding invented to be the densest possible within printable ASCII, at roughly 23% overhead.
91 symbols encode about 6.5 bits per character, versus 6 bits per character for Base64's 64 symbols.
All printable ASCII characters except the hyphen, single quote, backslash, and space — 91 symbols.
Less so than Base64 or Base85. It is primarily a niche/compactness encoding rather than a universal standard.
Yes. Upper and lowercase letters and punctuation all have distinct values.
Never. All conversion happens locally in JavaScript.