Base64 Encoder / Decoder
Convert plain text to Base64, or decode a Base64 string back to plain text — both directions, one page.
What Base64 is for
Base64 turns arbitrary bytes — including text with special characters — into a string of 64 printable characters (A–Z, a–z, 0–9, + and /), which is why it's used to embed binary data like images inside text formats such as JSON, HTML, or email. It is an encoding, not encryption: anyone can decode it back, so it shouldn't be used to hide sensitive information.
Common uses
- Decoding a Base64 payload found in an API response or JWT token
- Embedding a small image directly into CSS or HTML as a data URL
- Passing text safely through systems that don't handle special characters well
Frequently asked questions
Is Base64 the same as encryption?
No — Base64 is an encoding, not encryption. Anyone can decode a Base64 string back to its original form with no key or password required, so it should never be used to hide sensitive information.
Why does Base64 make text longer?
Base64 represents every 3 bytes of original data as 4 characters, so encoded text is roughly 33% larger than the original. That overhead is the trade-off for being able to safely represent binary data as plain text.
Can I decode a JWT token with this tool?
You can decode the header and payload segments of a JWT (the parts between the dots) since they're Base64-encoded JSON — paste just one segment at a time. Note this only decodes the readable content; it doesn't verify the token's cryptographic signature.
Why did decoding fail with an error?
This usually means the pasted text isn't valid Base64 — it may contain characters outside the standard Base64 alphabet, have been truncated, or actually be plain text that was never encoded in the first place.