HTML To Base64 Converter

Convert any HTML markup into a UTF-8 safe Base64 string instantly in your browser. Use the encoded payload inside data URIs, email templates, configuration files, or anywhere binary-safe transport of HTML snippets is needed.

Why encode HTML as Base64?

• Data URIs: Embed a full HTML document into an iframe src="data:text/html;base64,..." for sandboxed previews.
• Transport safety: Avoid line-break, quoting, and encoding issues when shipping HTML through JSON APIs, environment variables, or query parameters.
• Email templates: Some delivery services require Base64-encoded body parts for inline HTML attachments.
• Snapshots: Persist rendered HTML to logs or databases as a single opaque string.

How the conversion works

The tool reads your raw HTML, encodes it to UTF-8 bytes with the browser's native TextEncoder, and then transforms those bytes to a Base64 ASCII string with btoa. This avoids the silent data loss that occurs with the older btoa(unescape(encodeURIComponent(...))) trick when the input contains emoji or characters outside the Latin-1 range.

Common pitfalls to avoid

• Do not include HTTP headers or shell prompts in the input — only the HTML markup itself.
• When wrapping the result in a data URI, remember to URL-encode characters like +, /, and = if the URI is used inside JSON or query strings.
• If you need a URL-safe variant, replace + with -, / with _, and strip trailing = padding manually.