What is the difference between Adobe ASCII85 and RFC 1924?

Adobe ASCII85 uses characters ! through u (ASCII 33–117) plus z as a shorthand for four zero bytes, and wraps output in delimiters. RFC 1924 uses a different 85-character alphabet (digits, letters, and selected symbols) without delimiters. Both encode 4 bytes as 5 characters.

Do I need to include the delimiters when decoding Adobe ASCII85?

No. The decoder automatically strips delimiters if present, so you can paste the raw encoded body or the complete delimited string — both work correctly.

Why does decoding fail with "not valid UTF-8"?

The Base85 string decodes to raw bytes that cannot be interpreted as valid UTF-8 text. This typically means the original data was binary (an image, executable, etc.) rather than a plain text string. This tool is designed for text-in / text-out workflows.

Is my data sent to a server?

No. All decoding runs entirely in your browser using JavaScript. Your input never leaves your device.

What does the z character mean in Adobe ASCII85?

In Adobe ASCII85, z is a shorthand representing a group of four zero bytes (0x00000000). It replaces the five-character sequence !!!!! and makes zero-heavy data significantly shorter.

How is Base85 different from Base64?

Base85 encodes 4 bytes as 5 ASCII characters (~25% overhead), while Base64 encodes 3 bytes as 4 characters (~33% overhead). Base85 is more space-efficient but requires a larger character set and is slightly more complex to decode.

Base85 Decoder

Name: Base85 Decoder
Availability: InStock
Author: Nham Vu

Paste a Base85 or ASCII85 encoded string and instantly decode it back to the original text — no server needed.

Variant:

Base85 Encoded Input 0 chars

Decoded Output 0 chars

Copied!

Summary

Paste a Base85 or ASCII85 encoded string and instantly decode it back to the original text — no server needed.

How it works

Paste your Base85 or ASCII85 encoded string into the input field.
Select the correct variant: Adobe ASCII85 or RFC 1924.
Click the Decode button to convert the encoded text back to the original string.
The decoded output appears in the result panel immediately.
Use the Copy button to copy the decoded text to your clipboard.
All processing runs entirely in your browser — nothing is sent to any server.

Use cases

Decode ASCII85 payloads extracted from PDF or PostScript files.
Reverse RFC 1924 Base85 strings produced by Git or ZeroMQ.
Verify that a Base85 encoded string matches the expected plaintext.
Inspect Base85 encoded data during security research or forensics.
Quickly decode Base85 snippets found in source code or network captures.
Test encoding/decoding round-trips when developing encoding utilities.
Recover text from Base85 encoded clipboard content or log files.
Understand the difference between Adobe and RFC 1924 Base85 alphabets.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu