What is Base85 Encoding?
Base85 (also known as Ascii85) is a binary-to-text encoding scheme that converts binary data into ASCII text using 85 printable characters. It encodes 4 bytes of binary data into 5 ASCII characters, making it approximately 25% more efficient than Base64. The Adobe Ascii85 variant wraps output in <~ and ~> delimiters and uses the special 'z' character to represent four consecutive zero bytes for compactness. RFC 1924 uses a different character set optimized for IPv6 address representation.
How to Use
- Select the mode: Encode (text → Base85) or Decode (Base85 → text).
- Choose the variant: Ascii85 (Adobe) or RFC 1924.
- For encoding, optionally enable <~ ~> delimiters and line wrapping.
- Enter your text or Base85 data in the input field.
- Click 'Encode' or 'Decode' to convert.
- Copy the result using the Copy button.
Why Use This Tool?
Tips & Best Practices
- Base85 is less widely supported than Base64 — use it when you need compactness
- The Adobe Ascii85 format with <~ ~> delimiters is the most common variant
- The 'z' character in Ascii85 represents 4 zero bytes, making null-heavy data very compact
- RFC 1924 was designed for IPv6 addresses but can encode any binary data
- Base85 output is about 25% larger than the input, compared to Base64's 33%
- Use our Base64 encoder for broader compatibility when Base85 isn't required
Frequently Asked Questions
What is Base85 encoding?
Base85 (Ascii85) is a binary-to-text encoding that converts 4 bytes of binary data into 5 ASCII characters using 85 printable characters. It's about 25% more efficient than Base64, which converts 3 bytes into 4 characters (33% overhead).
How does Base85 compare to Base64?
Base85 produces smaller output than Base64 for the same input. Base64 has 33% overhead while Base85 has only 25% overhead. However, Base64 is more widely supported and uses a simpler character set. Use Base85 when compactness matters, such as in PDF files.
What is the Adobe Ascii85 format?
Adobe Ascii85 wraps the encoded output with <~ and ~> delimiters. It also uses the special 'z' character to represent four consecutive zero bytes, making the encoding more compact for data with many null bytes. This is the format used in PDF and PostScript.
What is RFC 1924?
RFC 1924 defines an alternative Base85 encoding with a different character set (0-9, A-Z, a-z, and special characters). It was proposed for compact IPv6 address representation but can encode any binary data.
Is my data sent to a server?
No, all encoding and decoding happens entirely in your browser. Your data is never sent to any server. No data is collected, stored, or transmitted.
Real-world Examples
Encoding Text with Adobe Ascii85
The classic example: encoding 'Hello, World!' produces the Ascii85 string with Adobe delimiters.
Hello, World!
<~87cURD_*#TDfTZ)~>
Zero Byte Compression
Four zero bytes are encoded as a single 'z' character in Adobe Ascii85, making null-heavy data very compact.
\x00\x00\x00\x00
<~z~>