Base64 encoding and decoding: what it is and how to do it

Developer 22 October 2026 5 min read

Base64 turns bytes into plain letters and digits so they can travel through systems that only handle text, such as email, JSON or URLs. Base64 encode/decode converts both ways.

Steps

Paste your text.
Pick the Direction: encode or decode.
Optionally tick the URL-safe alphabet, which uses - and _ and drops the = padding.
Copy the result.

Example

abc encodes to YWJj. Decoding YWJj returns abc. Text with accents, Hindi or emoji works too because the tool encodes it as UTF-8 first.

Base64 is not encryption

Anyone can decode Base64 in seconds. It hides nothing. Never use it to protect passwords or secrets.

When to use URL-safe

Standard Base64 includes +, / and =, which have special meanings in URLs. JSON Web Tokens use the URL-safe form; see JWT explained.

Common errors

“Invalid input” when decoding usually means extra characters, such as spaces or quotes, or a URL-safe string decoded in standard mode.
Garbled text after decoding often means the data was not text at all (for example an image).

For percent-encoding in web addresses, use URL encode/decode.