Developer & Data ToolsEncoding & Decoding

Base64 Encoder / Decoder

Encode UTF-8 text as Base64 or decode a Base64 string back to text. The page explicitly distinguishes reversible encoding from encryption and password protection.

Browser-localFreeNo upload required

Tool workspace

Text to encode or decodeOr choose an image (maximum 5 MB)

Base64 result

What this tool is for

Encode UTF-8 text as Base64 or decode a Base64string back to text. The page explicitly distinguishes reversible encoding from encryption and password protection.

How to use

Choose Encode or Decode for the direction you need.
Paste text or a Base64 value and run the conversion.
Inspect the decoded characters before using the result in an API, configuration file, or test fixture.

Example

Encode `Hello, 世界` and decode the generated value to confirm that the UTF-8 text round-trips correctly.

FAQ

Is Base64 encryption?

No. Anyone can decode it; do not use it to protect secrets.

Does this handle files?

This page handles text. Binary file conversion requires a file-specific tool.

Reproducible examples

Known inputs and expected results

Run these examples in the workspace above and compare the result with the documented output.

ASCII round trip

Input: Hello
Options: Choose Encode, then Decode.
Action: Encode the text and decode the result.
Expected output: SGVsbG8=, which decodes back to Hello.
Explanation: The ASCII bytes map directly into standard Base64 groups.

UTF-8 text round trip

Input: 你好
Options: Use standard Base64 text mode.
Action: Encode and decode.
Expected output: 5L2g5aW9, which decodes back to 你好.
Explanation: The string is converted to UTF-8 bytes before Base64 encoding.

Error or unsupported case

Wrong dialect or padding

Input: SGVsbG8_
Expected error or limit: The underscore belongs to Base64URL and is not silently treated as standard Base64.
Safer alternative: Normalize the documented Base64URL alphabet and padding with a JWT/Base64URL-aware tool.

When not to use this tool

Encryption, hashing, password protection, or secret storage
Arbitrary binary file conversion in the text-only workspace

Algorithm and assumptions

Text uses UTF-8 bytes and the standard +/ alphabet with padding; decoding must produce valid UTF-8 and does not imply authenticity or confidentiality.

Input and output

Input is UTF-8 text or Base64 text. Output is a Base64string or decoded UTF-8 text.

Supported formats and behavior

Unicode text through UTF-8
Standard Base64 alphabet
Visible errors for invalid encoded input

Limits

No file upload on this page
URL-safe Base64 variants may need `-`/`_` normalization and padding

Edge cases and common errors

Missing padding can be browser-dependent
Decoded bytes that are not valid UTF-8 may not display as intended
Whitespace in encoded input is normalized conservatively

Release testing

Release checks cover ASCII and Unicode round trips, empty input, invalid Base64, copy, and clear behavior.

Privacy boundary

The input and result stay in this browser session. ZZP Box does not upload or store the values entered in this tool.

Related reviewed tools

Choose the next tool by the operation you need, then review that page's stated input and limits.