Base64 Encoder / Decoder guide

How to Encode and Decode Base64 Text or Files

Convert Unicode text or local file bytes to Base64, decode URL-safe data and inspect binary results without confusing encoding with encryption.

Open Base64 Encoder / Decoder →

Before you start

Decide whether the input is text to encode or Base64 to decode. Auto-detect is only a suggestion; explicit Encode and Decode actions remain available.
Know whether the source uses standard Base64 or Base64URL. URL-safe data replaces + and / with - and _.

Step-by-step instructions

Open the Base64 Encoder / Decoder and paste text, or open a local file to work with its original bytes.
Click Encode to create Base64. Enable URL-safe if the destination expects the alternate alphabet and unpadded output.
To reverse the conversion, paste Base64, select the appropriate alphabet and click Decode.
Inspect decoded UTF-8 text or hexadecimal bytes. Binary bytes may not be readable as text.
Copy the output or download the decoded bytes when recovering a file. Check the result with the application intended to open that file.

Text round trip

This example uses standard Base64. Encoding the five UTF-8 bytes of Hello produces SGVsbG8=. Decoding it returns Hello. The = character is padding, not an encrypted suffix.

Text: Hello
Standard Base64: SGVsbG8=
Decoded text: Hello

Text, binary data and URL-safe encoding

Text is converted to UTF-8 bytes so accents and emoji can be represented. A binary file can contain arbitrary bytes, so its decoded output may show replacement characters in text mode. Use hexadecimal inspection or a byte download instead.

Base64 is reversible encoding, not encryption or a way to protect a password. A full JWT contains dot-separated segments and should be opened in the JWT decoder. Copy the actual Base64 portion when a source wraps it in another format; this tool does not fetch remote URLs or promise a file-format conversion.

Troubleshooting

Decode reports invalid input

Check the alphabet setting, unexpected wrapper text and whether the string was truncated. Do not treat arbitrary text that happens to use Base64 characters as proof that decoding was intended.

Decoded output looks like gibberish

The bytes may represent a binary file. Inspect hexadecimal output or download them, then open the file using a suitable application.

The downloaded file is not the format I expected

Base64 restores bytes; it does not turn them into a different file format. Confirm the original content and appropriate extension rather than relying only on a filename.

Privacy and cleanup

Text and local files are processed in your browser without uploading their contents. Local processing does not make encoded secrets safe to share. Download and clipboard actions are explicit.

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Related tools and guides

Use Base64 Encoder / Decoder with the steps above, or continue with a related task.

Technical references

These references explain the underlying formats or browser behavior. The steps above describe the current AnyUtils tool.

RFC 4648: Base64 and URL-safe encoding