Base64 Encoder & Decoder

Decode Base64 and Base64url into UTF-8 text, including Unicode and optional padding. Encode, copy or download text locally in your browser.

Example

Decode UTF-8 text, including Chinese and emoji.

Input

UTF-8 text only, up to 1 MiB. Images, binary files and data URLs are not supported. Invalid alphabets, lengths, padding and non-UTF-8 bytes get specific errors. Base64 is an encoding, not encryption. All processing stays on this device.

OptionsOperationAlphabet

Result

Your result will appear here after processing.

How do I decode Base64 text?

Paste Base64 text and choose Decode text, or switch Operation to Encode for plain text. Match the Alphabet to standard Base64 (+ and /) or Base64url (- and _). Decoding ignores whitespace and accepts omitted trailing padding. Use the examples to try Unicode and URL-safe input, then copy or download the result.

Base64 decoding examples

Paste the encoded text and choose Decode text. For Base64url, select the URL-safe alphabet first.

Decode UTF-8 text with Chinese and emoji

Input

SGVsbG8sIOS4lueVjCDwn5GL

Output

Hello, 世界 👋

Decode URL-safe Base64url

Input

8J-Yig

Output

😊

Decode text without trailing padding

Input

Zg

Output

Why does Base64 decoding fail?

Check the selected alphabet and padding. Zg and Zg== both decode to f, but Zg= has incomplete padding. A string such as /w== is valid Base64 but does not contain valid UTF-8 text. This text tool cannot restore an image, PDF or other binary file.

What can I do with decoded text?

Copy your result before opening another tool, then paste it there.

Format decoded JSON when the result is a JSON document.
Decode a URL component first if your encoded text contains percent escapes such as %2B.
Inspect a complete JWT with the JWT tool. JWT segments use Base64url; decoding does not verify a signature.

What does it support?

UTF-8 text only, up to 1 MiB. Images, binary files and data URLs are not supported. Invalid alphabets, lengths, padding and non-UTF-8 bytes get specific errors. Base64 is an encoding, not encryption.

Does my input leave my device?

No. Processing runs locally in your browser. Input and results are kept only on this page and are cleared when you leave, reload or clear the tool. Copy and download happen only when you choose those actions.