About Base64 Encoder/Decoder
Base64 Encoder/Decoder converts text to Base64 and back, entirely in your browser. Base64 is a way of representing binary or text data using only 64 printable ASCII characters, which makes it safe to embed in places that don't handle raw bytes well — JSON payloads, URLs, email attachments, HTTP Basic Auth headers, and data: URIs. Everything runs locally using the browser's own encoding APIs — nothing you paste is uploaded, logged, or stored anywhere.
How to use it
- 1
Paste your text
Paste plain text into the input pane to encode it, or paste an existing Base64 string to decode it.
- 2
Choose Encode or Decode
Click Encode to convert plain text to Base64, or Decode to convert Base64 back to readable text.
- 3
Copy or swap
Click Copy to copy the result to your clipboard, or Swap to move the output back into the input and run it the other way.
What it does
- Encodes any UTF-8 text to Base64
- Decodes Base64 back to UTF-8 text
- Validates that decoded input is well-formed Base64 before attempting to decode it
- Handles Unicode text correctly (emoji, accented characters, non-Latin scripts), not just ASCII
FAQ
Why does decoding sometimes fail with 'Invalid Base64 input'?
This happens when the input contains characters outside the Base64 alphabet (A–Z, a–z, 0–9, +, /, and = padding), has a length that isn't a multiple of 4, or decodes to bytes that aren't valid UTF-8 text. Copy-paste sometimes introduces stray whitespace or line breaks — those are stripped automatically before decoding, but other invalid characters will still be flagged.
Is Base64 encryption?
No. Base64 is an encoding, not encryption — it has no secret key and anyone can decode it instantly. It only changes how data is represented, not who can read it. Never use Base64 alone to protect sensitive data.
Why is the Base64 output longer than my original text?
Base64 represents every 3 bytes of input as 4 output characters, so encoded output is roughly 33% larger than the original. This is the tradeoff for using only printable, transport-safe characters.
Does this tool send my data anywhere?
No. Encoding and decoding both happen locally in your browser using the built-in TextEncoder/TextDecoder and btoa/atob APIs. Your input is never sent over the network.