Base64 Decoder

About Base64 decoder

Converts a Base64 string back into readable text, treating the decoded bytes as UTF-8. It accepts both the standard alphabet and the URL-safe Base64url alphabet, with or without padding, so a value from a config file, a log line, an email header, a token segment or an API response decodes without any preparation.

How to use it

1. Click the Decode tab above the input box, because the page opens on Encode.
2. Paste the Base64 string into the box labelled Base64 to Decode.
3. Press Decode from Base64.
4. Read the text in the Base64 Decoded Result panel, where a short note says which alphabet was detected, or press Copy to keep it.

Standard and URL-safe input

SGVsbG8sIFdvcmxkIQ==
8J-YgA (URL-safe, no padding)

Hello, World!
😀   (and Y2Fmw6k= decodes to café)

When to use it

• Reading the credentials inside a captured Basic authentication header to see which user was sent.
• Checking a value copied out of a Kubernetes secret manifest or an environment file.
• Unwrapping a Base64 body from a raw email or webhook while debugging why a parser rejects it.
• Confirming that text survives a round trip before you store it somewhere.

Questions about Base64 decoder

What error messages can it show?

Each one names the problem: a character that is not in either alphabet, a string that mixes plus or slash with hyphen or underscore, misplaced equals signs, a length that no Base64 string can have, or decoded bytes that are not valid UTF-8 text.

Do I have to keep the trailing equals signs?

No. Missing padding is tolerated, so SGVsbG8 decodes to Hello just like SGVsbG8=. Spaces and line breaks in the middle of a pasted value are ignored as well, but equals signs anywhere except the end are rejected.

Can I decode a picture or a ZIP file here?

The result panel shows text, and raw binary is rarely valid UTF-8, so you will usually get an error. For pictures, the Base64 to Image tool is the right place.

What if the original text was not UTF-8?

Bytes from an older single-byte encoding often fail validation outright or produce garbled symbols. Re-encode the source as UTF-8 if you control it.

Does decoding happen on your servers?

It happens locally in your browser, using built-in text decoding. The string is never transmitted.

Related tools

• Base64 encoderEncode any string input to Base64.
• Base64 to ImageDecode Base64 input to an image.
• URL decoderDecode URL input to back to a normal string.
• Image to Base64Transform an image input to a Base64 string.
• Binary converterConvert text to binary and the other way for any string input.
• Ascii converterConvert text to ascii and the other way for any string input.