Base64
Encode and decode Base64 online
Encode and decode text, a URL-safe string or a data URL. All of it runs in the browser.
What this Base64 tool can do
- Encode and decode in one click
- URL-safe alphabet for tokens and links
- MIME wrapping at 76 characters per line
- Files up to 5 MB: PDF, ZIP, images
- Data URL builder for embedding
- Input and output byte sizes
How to encode or decode Base64
Paste the text
Insert the string you want to encode or the Base64 you want to decode.
Pick a mode
Choose Encode or Decode and toggles like URL-safe or MIME wrap.
Copy the result
The output appears instantly with its byte size — copy it in one click.
Build a data URL
Optionally wrap the output as a data URL for HTML or CSS embedding.
Frequently asked questions
What is URL-safe Base64?
It replaces + and / with - and _ and drops padding, so the string survives inside URLs and filenames without escaping.
Why does Base64 end with =?
Padding makes the output length a multiple of 4 characters. One or two = signs are normal — decoders expect them.
Is my text sent to a server?
No. Encoding runs entirely in your browser — nothing is uploaded.
What is MIME wrapping?
Email standards wrap Base64 at 76 characters per line. Enable it when preparing content for MIME messages.