Base64 encode and decode

How to use

1. Choose "Encode" or "Decode".
2. To encode, choose "Text" or "File". A chosen file is encoded right away. Turn on "Output as a data URL" to embed it in HTML or CSS, or "URL-safe" for use in URLs and file names.
3. To decode, paste Base64 or a data URL (data:…;base64,…) and press "Decode". Standard and URL-safe Base64 are detected automatically.
4. Copy the result or use "Save as file". "Use result as input" lets you convert back right away.

Supported formats and limits

• Text input up to 5 MB and files up to 5 MB.
• Text is treated as UTF-8. Base64 made from text in another encoding cannot be turned back into readable text here. Line breaks typed into the box are encoded as LF (browser behavior).
• If the decoded data is not UTF-8 text (for example an image), it is not shown as text; a hex dump and a save button are shown instead. The file extension comes from the data URL type or the first bytes (PNG, JPEG, GIF, WebP, PDF, ZIP and a few more), otherwise .bin.
• Data URLs always use standard Base64, so the URL-safe option is ignored for them. Data URLs that are not Base64 (no ";base64,") cannot be decoded.
• Base64 is not encryption. Anyone can decode it.

How it works

Encoding converts text to UTF-8 bytes, or takes a file as raw bytes, and then applies Base64 as defined in RFC 4648. URL-safe output uses - and _ instead of + and / and omits the trailing = padding.

A data URL is "data:<file type>;base64," followed by the Base64 (RFC 2397). The file type is the one your browser reports for the file.

Decoding accepts both the standard and the URL-safe alphabet. Spaces and line breaks are ignored, and missing = padding is tolerated. Any other character is reported with its position.

The decoded bytes are read as strict UTF-8. If they are not valid UTF-8, no garbled text is shown; the tool says the data is not text.