Base64 Online Decoder Tool
Base64 Online Decoder provides Base64 encoding, online Base64 decoding, Base64 encryption and decryption. It encrypts strings into Base64 format and decodes encrypted Base64 strings to display plaintext. Base64 is a common online encryption algorithm. When addressing Chinese character garbling issues, encoding Chinese text using different methods can effectively prevent such garbling. No information is stored—use with confidence.
Base64 Index Table
Base64 encoding converts any byte sequence into an ASCII string using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /), with the “=” symbol serving as a suffix.
| Numeric | Character | Numeric | Character | Numeric | Character | Numeric | Character |
| 0 | A | 16 | Q | 32 | g | 48 | w |
| 1 | B | 17 | R | 33 | h | 49 | x |
| 2 | C | 18 | S | 34 | i | 50 | y |
| 3 | D | 19 | T | 35 | j | 51 | z |
| 4 | E | 20 | U | 36 | k | 52 | 0 |
| 5 | F | 21 | V | 37 | l | 53 | 1 |
| 6 | G | 22 | W | 38 | m | 54 | 2 |
| 7 | H | 23 | X | 39 | n | 55 | 3 |
| 8 | I | 24 | Y | 40 | o | 56 | 4 |
| 9 | J | 25 | Z | 41 | p | 57 | 5 |
| 10 | K | 26 | a | 42 | q | 58 | 6 |
| 11 | L | 27 | b | 43 | r | 59 | 7 |
| 12 | M | 28 | c | 44 | s | 60 | 8 |
| 13 | N | 29 | d | 45 | t | 61 | 9 |
| 14 | O | 30 | e | 46 | u | 62 | + |
| 15 | P | 31 | f | 47 | v | 63 | / |
Base64 splits the input string into bytes, obtains the binary value corresponding to each byte (padding with leading zeros if less than 8 bits), concatenates these binary values, then splits them into groups of 6 bits (since 2^6 = 64). If the last group has fewer than 6 bits, trailing zeros are added. Each group of binary values is converted to decimal, and the corresponding symbol from the table above is found and concatenated to produce the Base64 encoded result.
Base64 can be used for encoding the underlying binary data of any type, enabling transmission in scenarios where only ASCII characters can be sent. However, it is most commonly used for processing and transmitting text data. For example, in MIME-formatted emails, Base64 can encode email content to facilitate transmission between computers with different languages without garbling. Note that this refers to transmission, not display. For instance, Chinese characters can be displayed normally on Western European computers using UTF-8 encoding (provided the corresponding font library is installed), but they may not transmit correctly. Converting to Base64 eliminates this concern.
Unless otherwise specified, Base64 encoding typically treats non-ASCII characters as UTF-8 encoded.
