Free Base64 Encoder & Decoder — Online Tool
Encode text or data to Base64 and decode Base64 strings back to plain text.
About this tool
Encode any text to Base64 or decode a Base64 string back to readable text instantly. Useful for working with data URIs, HTTP headers, email attachments, and API payloads. Fully browser-based with no data ever leaving your device.
Key Features
- Encode plain text to Base64 in one click
- Decode Base64 strings back to readable text instantly
- Handles Unicode and special characters correctly
- Copy result to clipboard with a single button
- 100% client-side — your data stays private
Frequently Asked Questions
What is Base64 encoding used for?
Base64 is used to represent binary data in an ASCII string format. Common uses include embedding images as data URIs, encoding credentials in HTTP Basic Auth headers, handling email attachments, and passing binary data in JSON or URL parameters.
Can I decode any Base64 string with this tool?
Yes, as long as the Base64 string is valid and the decoded result is valid UTF-8 text. If the decoded bytes are not valid UTF-8 (e.g., binary files), the output may contain unreadable characters.
Does this tool handle URL-safe Base64?
Standard Base64 uses + and / characters. If your string uses - and _ instead, it is URL-safe Base64. The tool handles standard Base64; for URL-safe variants, replace - with + and _ with / before decoding.
Is there a size limit on what I can encode or decode?
No server-side limit exists since everything runs in your browser. You can encode or decode strings of any length your browser's memory supports.