Base64 Encoder / Decoder
Encode and decode Base64 text with full UTF-8 and URL-safe support.
Plain text
Base64
What is Base64?
Base64 encodes binary data using 64 ASCII characters, expanding the size by roughly 33%. It is widely used in email attachments (MIME), inline images (data URLs), JSON Web Tokens, and HTTP Basic auth headers β anywhere binary needs to travel through a text-only channel. URL-safe Base64 swaps + and / for - and _ so the output can be placed directly into URLs without further encoding.
About this tool
A free, browser-based Base64 encoder and decoder. Convert any text to Base64 and back, with full UTF-8 support for emoji and unicode, plus a URL-safe variant for use in URLs and JWTs.
How to use it
Quick steps to get the most out of this utility.
- 1
Choose Encode or Decode
Switch between converting text to Base64 and decoding Base64 back to text.
- 2
Pick the variant
Standard Base64 uses + / =. URL-safe Base64 swaps + and / for - and _ and drops padding.
- 3
Paste input
Output appears instantly as you type. Errors highlighted clearly if input is not valid Base64.
- 4
Copy or swap
Use Copy to grab the result, or Swap to feed the output back as input for the opposite operation.
A 60-second Base64 explanation
Computers store data as bytes (0β255). But many transport channels β email headers, URL query strings, HTTP Basic auth β only allow a limited set of printable ASCII characters. Base64 solves this by mapping every 3 bytes of binary into 4 characters from a 64-character alphabet (A-Z a-z 0-9 + /).
The output is always ASCII, always safe to paste into emails or JSON, and always reversible. The cost is a ~33% size increase β perfectly acceptable for the small payloads where Base64 shines.
When NOT to use Base64
- For large files β the 33% overhead is wasteful when you could use a binary upload.
- For secrets β Base64 is encoding, not encryption. Anyone can decode it.
- For database storage of files β modern databases support binary columns natively.
Frequently asked questions
What is Base64 used for?+
Base64 is used to transmit binary data over text-only channels β email attachments (MIME), inline images (data URLs), JSON Web Tokens, HTTP Basic auth headers, and config files. It encodes 3 bytes of binary as 4 ASCII characters, expanding size by ~33%.
When should I use URL-safe Base64?+
When the encoded value will be placed in a URL or filename. Standard Base64 uses + and / which have special meaning in URLs. URL-safe Base64 swaps them for - and _ and removes the trailing = padding.
Is Base64 a form of encryption?+
No. Base64 is encoding, not encryption. Anyone who sees a Base64 string can decode it instantly. Use Base64 to transport binary data, never to hide secrets.
Why does my Base64 string contain "="?+
The "=" characters at the end are padding. Base64 always works in groups of 4 characters; if your input doesn't divide evenly, padding is added so it does. URL-safe variants typically drop the padding.
Does this work with emoji and unicode?+
Yes. The tool encodes input using UTF-8 first, then converts to Base64. This means π, δΈζ, and any other unicode round-trips correctly.
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