What is Base64?
Also known as: base-64 encoding.
Last updated: July 2026
- Base64
- Base64 (specified in RFC 4648) is a binary-to-text encoding that represents data using 64 printable ASCII characters. It lets binary data travel safely through text-only channels such as email or data URIs. Encoding grows the data by about 33%, because every 3 bytes become 4 characters. It is encoding, not encryption — it provides no security.
Encode text to Base64 or decode Base64 back to text instantly. Free, private, in-browser — supports full Unicode (UTF-8).
Why Base64 exists
Many older systems — email (MIME), URLs, JSON, HTML data URIs — were designed for text, not raw bytes. Base64 maps arbitrary binary into a safe 64-character alphabet (A–Z, a–z, 0–9, + and /) so it survives those channels intact. The URL-safe variant swaps + and / for - and _.
It is not encryption
Base64 is fully reversible by anyone with no key, so it offers zero confidentiality. Use it to transport data, not to protect it. To secure data you need encryption; to verify integrity you need a hash or signature.
FAQ
Does Base64 make data bigger?
Yes — by roughly 33%, since every 3 bytes are encoded as 4 characters.
Is Base64 secure?
No. It's an encoding, not encryption — anyone can decode it without a key.
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