Base64 Encoder

Free Online Base64 Encoder & Decoder

Encode and decode Base64 strings instantly in your browser. Convert text to Base64 and back with our free tool. Perfect for developers working with APIs, data URIs, and encoded content.

Type or paste text into the input field and select Encode to convert it into Base64 format, which represents binary data as ASCII text. The encoded output uses A-Z, a-z, 0-9, and +/= characters. Select Decode to reverse the process, converting Base64 strings back to readable text. The tool handles Unicode characters correctly, encoding them as UTF-8 bytes before Base64 conversion. You can also encode binary files by uploading them, producing a Base64 string suitable for embedding in JSON or data URIs. Everything processes locally in your browser.

Web developers embed small images or icons directly in CSS or HTML using data URIs, which require Base64-encoded image data. API engineers encode authentication credentials for HTTP Basic Auth headers that require base64-formatted username:password pairs. Email developers encode image attachments inline in HTML emails rather than referencing external URLs that might be blocked. Frontend engineers decode Base64 strings from APIs to extract embedded binary files like PDFs or images that were serialized for JSON transport.

Base64 increases data size by approximately 33 percent, so only use it for small files or when embedding is genuinely necessary. When encoding sensitive data like tokens or credentials, remember that Base64 is encoding, not encryption—anyone can decode it instantly. For data URIs in CSS, balance convenience against cache efficiency; external files can be cached, but data URIs are re-downloaded every time the stylesheet loads. If you're decoding Base64 from an API and it looks like garbage, verify that the original encoding used UTF-8 rather than a different character set.

All processing happens directly in your browser. Your files never leave your device — no server uploads, no cloud storage, no data retention. The tool works offline once loaded, requires no registration, and is completely free with no usage limits.