What does it do?
It encodes text or files to Base64 and decodes Base64 back to text, images or files. It supports:
- UTF-8 text, including accents and emoji.
- Base64URL (
- and _, no padding), as used by JWTs.
- Data URLs (
data:image/png;base64,…) in both directions.
- Files of any type, with a preview for images and a download button when decoding binary data.
How to use it
- To encode, type text or press Encode a file.
- To decode, switch to Decode and paste Base64, Base64URL or a data URL. Whitespace and line breaks are ignored.
- Press Swap to send the result back to the input in the other mode.
Size
Base64 turns every 3 bytes into 4 characters, so the encoded text is about 33% larger than the original. Embedding big images as data URLs makes pages heavier and prevents caching; keep it for small icons.
Frequently asked questions
›Is Base64 encryption?
No. Base64 is an encoding: anyone can decode it. It only turns binary data into text that is safe to put in JSON, URLs, emails or HTML.
›What is the difference between Base64 and Base64URL?
Base64URL replaces + with - and / with _, and usually drops the = padding, so the result can go in a URL or a filename. JWTs use Base64URL.
›Why does my text with accents decode as strange characters elsewhere?
Because the browser's btoa only accepts Latin-1. This tool encodes text as UTF-8 first, which is what every modern system expects.