Base64 Decoder
Decode Base64 strings to UTF-8 text online. Accept standard Base64, Base64URL and Data URIs, check invalid padding, and download the original bytes without uploading data.
Your result will appear here.
How to decode a Base64 string
- Paste the Base64 value or complete Base64 Data URI. Decode is already selected.
- Decode the input. Copy readable text, or download the original bytes if the result is a file.
- For an image preview, use Base64 to Image. For a complete JWT, use the JWT decoder to inspect its separate parts.
Working with Base64 Decoder
Paste the encoded value, not an HTML tag or a quoted JSON string. Valid standard and URL-safe Base64 are accepted, with or without valid padding; spaces, tabs and line breaks are ignored. UTF-8 bytes become readable text. Other bytes remain downloadable unchanged, with a hexadecimal preview when they are not valid UTF-8. This is decoding, not decryption or password recovery.
Example: Base64 back to UTF-8 text
- Input
SGVsbG8sIHdvcmxkISDwn5GL- Result
Hello, world! 👋
Questions about Base64 Decoder
Why do I see hexadecimal instead of readable text?
The decoded bytes are not valid UTF-8. They may be an image, archive or text in a different character encoding. Download preserves the original bytes; this tool does not guess legacy character encodings.
Can I decode without the = padding?
Yes, when the remaining length and bits are valid. Missing padding is accepted; incorrect padding, mixed standard and URL-safe alphabets, and invalid trailing bits are rejected. A truncated string cannot recover missing bytes.
Can I paste a Data URI, URL parameter or JSON value?
A complete data:…;base64,… URI works. For JSON, copy the string value without quotes. Decode URL percent escapes first if present, and do not replace + with a space: that changes the Base64 value.
Does decoding a token prove it is genuine?
No. Base64 is a reversible representation, not encryption or a signature check. A JWT has dot-separated parts; use the JWT tool to read its header and payload, not to verify authenticity.
Are my files, tokens or text uploaded?
No. These tools process your input in your browser. The website serves the page and its code, but your input is not sent to a conversion server or saved in an account.
Related tools for your next step
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Turn Base64 strings and Data URIs back into downloadable files without changing the decoded binary data.
- Base64 to Image
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- Base64URL Encoder & Decoder
Convert text to URL-safe Base64 with the - and _ alphabet. Encode or decode unpadded Base64URL strings.
- JWT Decoder
Read JWT headers and payloads, inspect expiry and activation times, and view claims without sending your token anywhere.
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Your input and files are processed on your device. Keep sensitive results out of shared clipboards and use a trusted device for private keys and tokens.