Base64 Decode
Free Base64 decoder: convert Base64 or URL-safe Base64 to UTF-8 text, accept data: URIs and line breaks, and see the exact invalid character and position.
How to use Base64 Decode
- 1Paste Base64 (or a data: URI) into the input box.
- 2Read the decoded text, or fix the character the tool points to if it reports an error.
- 3Copy the text, or use Download as file when the bytes are not text.
What makes it better
- Accepts standard and URL-safe Base64, padded or not
- Ignores whitespace and line breaks; strips data: URI prefixes
- Pinpoints the invalid character and its position
- Detects non-text bytes and offers the raw bytes as a download
- Switch to Encode on the same page
About Base64 Decode
Base64 Decode converts Base64 back into readable text. It accepts the standard and URL-safe alphabets, with or without = padding, ignores spaces and line breaks, and strips a data: URI prefix for you. If the input is damaged it names the first bad character and its position instead of guessing.
Common uses
- Read the payload of a JWT segment or a Basic Authorization header.
- Inspect a Base64 value found in a config file, log line or API response.
- Check why a Base64 string from another system will not decode.
- Recover the original text from a data: URI.
Example
Input
SGVsbG8sIFNlY3VyaXR5IFRvb2xzISDgpKjgpK7gpLjgpY3gpKTgpYcg8J+Riw==
Result
Hello, Security Tools! नमस्ते 👋
Good to know
- Decoded bytes are shown as text only if they are valid UTF-8. Images, archives and other binary data cannot be displayed, so the tool offers them as a file download instead.
- Text that was encoded in another charset such as Latin-1 may be reported as invalid UTF-8 even though the Base64 itself is fine.
- Decoding does not check a signature. Decoding a JWT payload only reads it, and says nothing about whether the token is genuine.
Base64 Decode FAQ
How do I decode Base64 to text?
Paste the Base64 into the input box and the decoded text appears on the right. The bytes are read as UTF-8, so accented letters, Indian scripts and emoji come back correctly.
Does it decode URL-safe Base64 and strings without padding?
Yes. Characters - and _ are treated like + and /, and missing = padding is fine as long as the length is otherwise valid. Mixed alphabets in one string are also accepted.
What does “Invalid character at position” mean?
Base64 only allows letters, digits, +, / (or - and _) and trailing =. The tool counts positions in your original text and shows the first character that does not belong, which is often a stray quote, comma or non-breaking space.
Why does the tool say the bytes are not valid UTF-8 text?
The Base64 is valid, but what it holds is not text, for example an image, a PDF or text in another charset. Use Download as file to save the raw bytes, or try the Base64 to Image page if it is a picture.
Can I paste a full data: URI?
Yes. Anything up to the comma in data:text/plain;base64,… is removed automatically. A data: URI without the ;base64 marker is plain percent-encoded text, so the tool tells you there is nothing to decode.