What is the Base64 Encoder & Decoder?
Base64 is a way of representing binary data as plain ASCII text, and this tool converts in both directions: text or files to Base64, and Base64 strings back to readable content. Developers reach for it constantly — embedding small images as data URIs in CSS, passing binary data through JSON APIs, storing credentials in environment variables, or inspecting the payload of a token during debugging.
On BConvert, everything is computed locally in your browser. Paste text or drop a file to encode it, flip to decode mode to reverse a string, and optionally generate a data-URI prefix with the correct MIME type for images. Since no data leaves your machine, it is safe to use with API keys, tokens, and certificates you would never paste into a server-side tool.
How to use it
- Provide your input — Paste your text into the input box, or drop a file to encode its raw bytes instead of text.
- Choose the direction — Switch between Encode and Decode mode depending on which direction you need to go.
- Add a data-URI prefix — For images, tick the data-URI option to get a ready-to-paste string with the correct MIME type prefix.
- Inspect the output — Check the output preview and character count, which helps spot padding or line-break issues in long strings.
- Copy or download — Copy the result with one click or download it as a text file for use in code and config files.
Common use cases
- Embed a small logo as a data URI in CSS so it loads with zero extra HTTP requests.
- Decode a token payload during debugging to inspect the claims and expiry inside.
- Encode binary credentials or certificates for storage in environment variables and JSON configs.
- Convert email attachments to Base64 when building raw MIME messages in a script.
Tips
- Base64 inflates data by about 33 percent — only embed small assets as data URIs, never full photos.
- Base64 is encoding, not encryption; anyone can decode it, so never use it to hide secrets.
- Strip line breaks from copied strings — some decoders choke on whitespace in pasted values.
- For UTF-8 text with emoji or non-Latin characters, this tool encodes correctly, unlike naive btoa calls.
Frequently asked questions
What is Base64 used for?
It represents binary data as plain ASCII text, which lets you safely embed images in HTML and CSS, pass binary through JSON APIs, and store credentials in environment variables.
Is Base64 secure or encrypted?
No — it is just an encoding. Anyone can decode a Base64 string instantly, so never rely on it for secrecy. Use real encryption for protection.
Can I encode an image file?
Yes, drop any image and you get its Base64 with an optional data-URI prefix, ready to paste into an image source or CSS url value.
Why does decoding fail sometimes?
Usually because of stray whitespace, missing padding characters, or a string that was URL-encoded first. Clean the string and try again.