QSTools
Base64 Encode / Decode
Encode or decode Base64 text and bytes.
Encoded and decoded in your browser — nothing is uploaded.
Enter text to encode or Base64 to decode.
About this tool
This Base64 encoder/decoder converts UTF-8 text to Base64 and back entirely in your browser. Use standard Base64 for APIs and email payloads, or URL-safe Base64 (RFC 4648 §5) when you need -/_ instead of +/ and optional padding — for example in JWT segments or query strings. Input never leaves your device.
FAQ
- Is my text uploaded?
- No. Encoding and decoding run locally with the Web APIs in your browser.
- What is URL-safe Base64?
- URL-safe Base64 replaces + and / with - and _ and usually drops = padding so the string survives in URLs and filenames. Toggle it when you are working with JWT-style segments or similar formats.
- Why does decode fail?
- The input must be valid Base64 (or URL-safe Base64 if that option is on). Extra characters, truncated strings, or binary that is not valid UTF-8 text will show an error.