Base64 Encoder Decoder Online Free
The free Base64 Encoder / Decoder converts text to Base64 encoding or decodes Base64 back to plain text instantly in your browser. No data is sent to a server — encode and decode sensitive strings safely.
What Is Base64?
Base64 is an encoding scheme that represents binary data as a sequence of printable ASCII characters. It uses 64 characters — A–Z, a–z, 0–9, +, and / — plus = as padding. Because these characters are safe to use in URLs, email headers, JSON strings, and HTML attributes, Base64 is the standard way to embed binary data in text-based contexts.
How to Encode and Decode
- Open the Base64 Encoder / Decoder.
- Select Encode or Decode mode.
- Type or paste your input text.
- The result appears instantly below.
- Click Copy to copy the output.
Common Uses of Base64
| Use Case | What Is Encoded | Why Base64 |
|---|---|---|
| HTTP Basic Auth | username:password | Authorization header must be ASCII-safe |
| JWT tokens | Header and payload JSON | URL-safe encoding for the token segments |
| Data URIs | Images, fonts, SVGs | Embed binary files directly in HTML/CSS |
| Email attachments (MIME) | Binary file contents | SMTP transfers text; binary needs encoding |
| API secrets in config | Binary keys or credentials | Store binary bytes in a text config file |
Base64 and Unicode Text
Base64 was designed for binary data, not text. When encoding Unicode text (non-ASCII characters like accented letters, Arabic, or Chinese), you need to convert the text to bytes first. The standard approach is UTF-8 encoding followed by Base64 encoding. The tool handles this automatically — paste any Unicode text and it will be correctly encoded.
When decoding, the tool assumes UTF-8 encoding and converts the bytes back to a Unicode string. If the original data was not UTF-8, the decoded output may appear garbled.
Base64 vs URL-Safe Base64
Standard Base64 uses + and / as the 62nd and 63rd characters. These have special meanings in URLs, so a variant called Base64url substitutes - for + and _ for /, and omits padding. JWTs use Base64url encoding for their header and payload segments. If you are decoding a JWT segment, use the JWT Decoder instead, which handles the Base64url variant automatically.
Base64 Is Not Encryption
Base64 is an encoding, not encryption. Encoded data can be decoded by anyone — there is no key or secret involved. Do not use Base64 to protect sensitive data. It is safe to use for embedding binary data in text formats, but it provides no confidentiality. For actual encryption, use standard cryptographic algorithms applied at the application level.
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