Input is rejected
remove surrounding quotes, confirm the Standard/URL-safe setting, check padding and verify that the value was not truncated.
Convert Base64 to binary bytes
Decode Base64 to binary bytes, review the restored output and copy or download it. Use the standard or URL-safe option required by the source.
Base64 utility · Fast, exact Base64 conversion
What this tool does
Paste the Base64 value and decode it to binary bytes. The tool returns the corresponding byte or text representation; it does not automatically validate, reformat or execute the result.
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Paste text or choose a file
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Encode, decode or inspect
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Review output and byte details
1. Input
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2. Action
3. Output
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4. Quick actions
5. Base64 information
DescriptionBase64 represents bytes as text; it is not encryption.
AlphabetA-Z, a-z, 0-9, +, /, =
Input size0 characters / 0 bytes
Output size0 characters / 0 bytes
PaddingUses = to complete a four-character group.
StatusReady
How it works
Input bytes
101010 111100 110101 ...
Split into 6-bit groups
101010 111100 110101 ...
Convert to indexes
42 60 53 ...
Base64 characters
q 8 1 ...
How to convert Base64 to binary bytes
Paste the Base64 string you want to decode.
Keep Decode selected and choose Standard or URL-safe Base64 when the control is available.
Review the output and byte information, then copy or download the result.
Output and format behavior
Each decoded byte is shown as an eight-digit binary group separated for readability. This is a byte view, not textual Unicode rendering.
Use Standard Base64 for the normal RFC 4648 alphabet. Use URL-safe only when the receiving system expects Base64URL; padding rules can differ by protocol.
Expert tip
Record byte order separately. Base64 preserves sequence, but it does not explain whether a multi-byte number is big-endian or little-endian.
When this is useful
Typical workflows include:
- Inspect or compare a small payload when the original representation is opaque or difficult to paste safely.
- Translate byte examples from protocol documentation, packet captures or debugger output into Base64.
- Create a reproducible test fixture without manually rewriting the source bytes.
Limitations and safety
Important constraints:
- Base64 normally adds about one third to the byte payload, before any data-URL prefix or surrounding markup.
- Base64 is reversible encoding, not encryption. Anyone who receives the string can decode the original bytes.
- Use only the numeric notation documented for this tool. Out-of-range, incomplete or mixed-notation byte values are invalid.
Troubleshooting
Numeric input fails
use only the notation and separators documented for this tool. An out-of-range or incomplete byte is invalid.
Frequently asked questions
What exactly is preserved?
Each decoded byte is shown as an eight-digit binary group separated for readability. This is a byte view, not textual Unicode rendering.
What input notation does this page expect?
Use the exact byte notation described for this tool. Decimal, binary, hexadecimal and octal inputs are handled by separate converters, and the wrong notation is rejected.
What is the difference between standard Base64 and Base64URL?
Standard Base64 uses + and /. Base64URL uses - and _ and may omit padding; choose the form required by the receiving system.
Why is my Base64 input rejected?
Check for unsupported characters, a Standard/Base64URL mismatch, damaged padding or a truncated value. Also remove surrounding quotes that are not part of the payload.
Related Base64 tools
Continue with the localized page that matches the next operation:
Convert binary bytes to Base64Convert Base64 to hexadecimal bytesConvert Base64 to octal bytesConvert Base64 to decimal ASCII byte codes
Paste your input above, run the conversion, and copy or download the result.