Base64 Encoder / Decoder – Free Online Encode & Decode Tool
About This Base64 Encoder / Decoder
Base64 is a way of representing binary or text data using only 64 printable characters, which makes it safe to embed inside places that don’t handle raw binary well, such as URLs, JSON payloads, email attachments, or CSS and HTML files. This tool converts plain text into Base64 or takes existing Base64 and converts it back to readable text, with several formatting options built in for different use cases.
The BigToolSite Team tested this converter against standard Base64 test strings, including edge cases with special characters and padding, to confirm both encoding and decoding produce correct, spec-compliant results.
Beyond basic conversion, you can encode or decode each line separately for batch processing, wrap output at 76 characters for MIME compatibility, switch to URL-safe Base64 for use in links and filenames, and enable strict decoding to catch invalid input rather than silently stripping bad characters.
If you’re working with encoded data that ends up in a URL, pair this with our URL encoder/decoder to handle the rest of the string safely. For comparing two Base64 outputs or decoded results side by side, the text diff checker makes spotting differences easy.
How to Use the Base64 Converter
- Choose “Base64 Encode” to convert text to Base64, or “Base64 Decode” to convert Base64 back to text.
- Paste your input into the text box.
- Check “Encode/Decode each line separately” if you’re processing multiple entries at once.
- Enable “Split lines into 76 character wide chunks” if you need MIME-compatible formatting.
- Enable “URL-safe encoding” if the output will be used in a URL or filename.
- Click “Process” to generate the output, then copy it or download it as a .txt file.
Example Usage
Type Hello World into the input box with “Base64 Encode” selected, and the tool returns SGVsbG8gV29ybGQ=. Paste that same string back in with “Base64 Decode” selected, and it returns the original Hello World. If you’re generating a token for a URL query parameter, enable URL-safe encoding first so the output doesn’t contain characters that need extra escaping.
Yes, it’s completely free with no signup required and no limits on how much data you can process.
Standard Base64 uses the characters + and /, which have special meaning in URLs. URL-safe Base64 replaces them with – and _ and removes padding, making the output safe to use directly in links and filenames.
This usually means the input contains characters that aren’t valid Base64, or the string is missing required padding. Enabling strict decoding will flag these issues instead of silently ignoring them.
No. Base64 is an encoding scheme, not encryption. It makes data safe to transmit in text-based formats, but anyone can decode it back to the original without a key or password.
No. Your input is processed to generate the output and is not saved or logged.
