H1_Base64 Encoder / Decoder - Text to Base64 | MultiTool

How it works

Choose Encode or Decode, paste your input and convert instantly. Encoding uses UTF-8 so emoji, accents and any Unicode text survive the round trip perfectly.

What Base64 is (and isn’t)

• Encoding, not encryption. Anyone can decode Base64 instantly — it protects formatting in transit, not secrecy.
• Size grows ~33% — every 3 bytes become 4 characters. Expected, not a bug.
• Where it shines: embedding images as data URLs in CSS/HTML, sending binary inside JSON, HTTP Basic auth headers, and the payload of JWTs.
• Never as security — hiding an API key in Base64 is the same as writing it in the open.

Base64 in the wild

Once you recognize the pattern — strings ending in = or ==, mixing A–Z, a–z, 0–9, + and / — you start seeing Base64 everywhere:

• Data URLs: small images embedded directly in CSS/HTML (data:image/png;base64,…) — no extra request. Our Image to Base64 tool does exactly this.
• Email attachments: SMTP only transports text; every email attachment you ever sent traveled as Base64 (which is why attachments grow ~33%).
• JWTs: the header and payload of a JSON Web Token are Base64-encoded JSON — decode one with our JWT decoder to see the structure.
• Basic Auth headers: Authorization: Basic dXNlcjpwYXNz is just Base64 of “user:pass” — trivially decodable, hence why HTTPS is mandatory.

Your privacy

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