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Base64 to Binary Converter
Decode Base64 or Base64url into 8-bit binary groups. Keep leading zero bytes and download the original binary data as a .bin file.
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Convert Base64 to Binary
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Detailed conversion guide
How to Convert Base64 to Binary
Base64 stores bytes using a 64-character alphabet. Decode the original bytes first, then write each byte as eight bits. QQD/ becomes 41 00 FF in hex, so the middle group is eight zeros.
Use 8-bit groups to see byte boundaries, or choose continuous bits for compact copying. Download .bin saves the raw bytes of the displayed result. Download Output saves the readable bit string as text.
| Input | Output | Meaning |
|---|---|---|
QQD/ | 01000001 00000000 11111111 | Three bytes, including zero and 255 |
AA== | 00000000 | One zero byte |
_w | 11111111 | Unpadded Base64url |
Show Base64 Bytes as Bits in JavaScript
This example starts with known valid standard Base64. The tool also validates padding and supports Base64url.
const raw = atob("QQD/");
const bits = Array.from(raw, byte => byte.charCodeAt(0)
.toString(2).padStart(8, "0")).join(" ");Raw Bytes, Padding, and Invalid Input
A binary byte can contain any value from 0 to 255, including values that are not valid UTF-8. Use the binary download to recover the original data without text decoding.
Remove a data URL header before pasting the payload. The converter rejects mixed alphabets, misplaced equals signs, impossible lengths, and nonzero padding bits. For example, AA== is valid; AB== is not.
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