About this tool
Base64 is a way of representing binary data — images, files, or arbitrary bytes — as plain ASCII text, using only the characters A–Z, a–z, 0–9, + and /. It exists because many systems (email, JSON, URLs, HTTP headers) were built to carry text safely, not raw binary. This tool encodes any text or file into a Base64 string, or decodes an existing Base64 string back into its original form, entirely in your browser tab. Nothing you paste or upload is ever sent to a server. Base64 output is roughly 33% larger than the input, since every 3 bytes of source data become 4 characters of output. It's commonly used for embedding small images directly in CSS or HTML, sending binary data through JSON APIs, encoding email attachments, and building HTTP Basic Auth headers or JWT tokens.
Frequently asked questions
Is Base64 encryption?
No. Base64 is an encoding scheme, not encryption — it provides zero security or confidentiality. Anyone can decode a Base64 string instantly. Never use it to hide sensitive data.
Why does my Base64 string end with = signs?
The = characters are padding, added when the input length isn't a multiple of 3 bytes, so the output aligns to full 4-character groups.
What's the difference between Base64 and Base64url?
Standard Base64 uses + and /, which have special meaning in URLs. Base64url replaces them with - and _ so the result is safe to use directly in URLs and filenames — this is what JWTs use.
Can I encode a whole file, not just text?
Yes — drop any file onto the tool and it will be read and encoded as Base64, useful for embedding small assets as data URLs.
Will decoding work on Base64 from any source?
Yes, as long as it's valid Base64 (or Base64url) text. Invalid or corrupted input will be flagged rather than silently producing garbage.