Base64 Encoder
Encode and decode Base64 strings instantly. Supports text and file input. Free online tool, no upload, runs in your browser.
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Frequently asked questions
- What is Base64 used for?
- Encoding binary data (images, files) as ASCII text so it can be safely embedded in URLs, JSON, emails, HTML, or CSS data URIs.
- Is Base64 encryption?
- No. Base64 is encoding, not encryption. Anyone can decode it trivially. Do not use Base64 to hide secrets.
- Why is Base64 output larger than input?
- Base64 uses 4 characters to represent every 3 bytes of input, making the output about 33% larger.
- Can I encode images as data URIs?
- Yes. The tool accepts file uploads and outputs `data:image/...;base64,...` that you can paste directly into HTML or CSS.
- What are the URL-safe and line break options for?
- URL-safe swaps + and / for - and _ and drops the padding so the string can sit in a URL or a JWT. The line break option wraps the output at 76 characters, which is what MIME email expects.
- Why does decoding fail on my string?
- Decoding rejects input that is not valid Base64, most often because a character was lost in a copy or the padding at the end is missing. Whitespace and line breaks are stripped automatically, so those are not the cause.