A QUICK WALKTHROUGH
How to use this tool
- Paste plain text to encode or a Base64 string to decode.
- Choose the operation and standard or URL-safe alphabet.
- Process; copy the text or download the actual decoded bytes.
How it works
Base64 maps groups of bytes to an ASCII alphabet. Standard mode requires complete groups with correct padding. Base64URL uses hyphens and underscores and can omit padding. Decoding checks canonical padding bits. UTF-8 decoding is strict: invalid byte sequences produce a hex preview and binary download, not replacement characters.
A practical example
Start with
Hello
What to expect
SGVsbG8=
Important considerations
Base64 is not encryption and offers no secrecy. A token encoded this way can still contain credentials. Internal whitespace is not automatically ignored; paste a clean encoded string.
1 MiB per input. Input remains in page memory until you reset or leave. Copy and download actions are initiated by you. No tool input is sent to a processing service.
One more useful detail
Why does a decoded file show hexadecimal?
Its bytes are not valid UTF-8 text. The binary download preserves them exactly.