Base64 Converter

What Base64 actually is

Base64 is not encryption — it is a way to represent arbitrary binary data using only 64 printable characters (A–Z, a–z, 0–9, plus + and /, with = as padding). It exists because a lot of systems — email headers, JSON fields, URLs, HTML attributes — can only carry text safely. Anyone can decode it, so it protects nothing; it only makes binary data survive a text-only channel.

The cost is size: every 3 bytes become 4 characters, so Base64 output is about 33% larger than the input.

Where you will run into it

Data URIs that embed an image directly in CSS or HTML, HTTP Basic Authentication headers, the three dot-separated segments of a JWT, email attachments, and binary blobs stuffed into JSON API payloads are all Base64. Decoding a JWT’s middle segment here is a quick way to read its claims — though note that doing so does not verify its signature.

Accents and emoji

Plenty of Base64 tools break on non-English text because the browser’s built-in encoder only understands single-byte characters. This one converts your text to UTF-8 bytes first, so accented characters, emoji and non-Latin scripts round-trip correctly. Everything runs in your browser — nothing you paste is uploaded.