Convert Arbitrary Base to ASCII Online
Decode numeric strings in any base (2-36) to ASCII text - space, comma, or newline separated. Free, client-side, instant, offline, secure.
Paste numeric tokens in any base from 2 to 36 and decode them back to ASCII text — separators can be spaces, commas, or newlines, and the decoder also handles Unicode code points.
How to Use Convert Arbitrary Base to ASCII Online
- Paste the numeric tokens into the input. Separate them with any mix of spaces, commas, or newlines - the tokenizer accepts
48, 65 6c\n6c 6fas five tokens without blinking. - Set the source base in the number box (2 for binary, 8 for octal, 10 for decimal, 16 for hex, 32 or 36 for compact encodings). Values outside 2-36 trigger an inline error and the output keeps its last valid value.
- Read the live output - the decoder repaints within 150 ms of every keystroke, so you can scan the result as you type without clicking a button.
- Watch the stats line under the output: it reports the chosen base, total tokens, how many decoded successfully, how many characters came out, and (if any) how many tokens were skipped as invalid for this base.
- Unicode beyond ASCII is supported - tokens above
0x7Fdecode throughString.fromCodePoint, so decimal128512with base 10 becomes😀rather than a mojibake byte. - Copy writes the decoded string to the clipboard, Download .txt saves a timestamped file named
decoded-base<N>-<iso>.txt, and Clear wipes both textareas + stats. - Press
Ctrl+Enter(⌘+Enteron Mac) to force a decode and copy the result in a single shortcut - useful when re-running after a base change.
Frequently asked questions
What is an “arbitrary base” in this tool?
Any positional number system from base 2 (binary) through base 36 – the usual suspects are binary, octal, decimal, and hex, but 32 and 36 are common for compact IDs. Base 36 uses digits 0-9 and letters a-z, giving the widest token space.
Which bases are supported?
Every integer base from 2 up to 36 inclusive. The decoder accepts both uppercase and lowercase letters for bases above 10, so FF and ff both decode to 255.
What is the default base?
Base 16 (hexadecimal). It is by far the most common representation for ASCII bytes, so pasting hex is the zero-click path on page load.
Is my data secure?
Yes. Every parse and decode step runs in your browser – nothing is uploaded, cached, or tracked. After the page loads you can disconnect the network and keep decoding indefinitely.
What separators are accepted between tokens?
Any mix of spaces, tabs, commas, or newlines. The tokenizer splits on [s,]+, so inputs from spreadsheets (comma-separated) or terminals (space-separated) both work without preprocessing.
Does it work offline?
Yes. HTML, CSS, and JavaScript are self-contained. Once the page has loaded, you can turn off Wi-Fi and the tool keeps working – useful on air-gapped machines.
Is it free?
Yes, 100% free with no cap on how much you can decode. No sign-up, no premium tier, no watermark.
What happens to tokens that are invalid for the chosen base?
They are skipped, not guessed. The stats line reports the skip count and the base, so you can spot typos quickly – for example pasting a hex token with base 10 selected will always be skipped.
Can it decode values above ASCII 127?
Yes. The decoder uses String.fromCodePoint, which handles the full Unicode range up to 0x10FFFF. Decimal 128512 with base 10 decodes to 😀, for example.
What about the reverse operation?
Use the sibling ASCII to Arbitrary Base converter. Both tools share the same token-splitting rules, so the output of one pastes cleanly into the other without manual cleanup.