Convert WebP to Base64

Base64 encodes every 3 bytes (24 bits) of input as 4 ASCII characters (each carrying 6 bits). So the encoded output is exactly 4/3 = 1.333× the input bytes, plus 0-2 trailing = padding chars. This overhead is unavoidable and identical for any binary content (PNG, JPEG, MP4, ZIP – all 4/3).

Browser MIME detection is mostly based on the file extension and is easy to spoof. A file named .webp with arbitrary contents will report image/webp but won’t actually be a WebP. Checking the RIFF/WEBP magic bytes catches this – if your file fails validation, it’s not a real WebP regardless of what the extension says.

The data URI includes the MIME-and-encoding prefix data:image/webp;base64, followed by the base64. Browsers need this prefix to know how to decode the embedded data. Raw base64 omits the prefix – useful for storing in JSON or databases where the type is recorded separately, then reconstructing the prefix at use time.

Honest answer: a 10 MB WebP becomes a ~13.3 MB base64 string, and rendering 13 million characters in a textarea slows your browser. The cap protects UI responsiveness – it’s NOT about browser stability or memory safety (modern browsers handle larger blobs fine, they’re just slow at painting huge text). Larger files: use the data URI directly via a JS Blob without textarea rendering.

No, this tool only validates WebP magic bytes. For PNG / JPEG / GIF / etc, use a generic image-to-base64 tool. The magic-byte check is what makes this tool WebP-specific.

No. Base64 is encoding, not encryption. Anyone with the encoded string can decode it instantly. Don’t put secrets in a base64 string and assume they’re hidden.

Saves an HTTP request – useful for small icons embedded in HTML/CSS for offline pages, emails, or single-file documents. Costs: 33% size overhead, no browser caching, slower initial parse. Worth it for icons/logos under ~5 KB; rarely worth it for larger images.

Because it’s part of the parent document (HTML/CSS), so it shares the parent’s cache lifetime. Each time the parent is fetched, the embedded data is fetched too. External image files get their own cache entry and can be revalidated independently.

No. FileReader runs in the browser. The tool works offline once loaded.

The decoder strips the data URI prefix if present, removes whitespace, converts URL-safe -/_ to standard +//, decodes via atob, then checks RIFF/WEBP magic bytes on the result. If valid, you get an image preview and can download the bytes as a .webp file.