decodes the Base64 data contained in a string and returns the result as a byte array.


decodes using the string using the specified encoding.


  • The result of BaseDecode["string"] is a ByteArray object.
  • Available encodings include:
  • "Base16"hexadecimal representation of byte values
    "Base64"default Base64 as described in the internet standard recommendation RFC 4648
    "Base85ASCII"Ascii85 or a85 encoding, with the "z shortcut"


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Basic Examples  (2)

Decode a Base64-encoded string:

Decode a byte array using using the Ascii85 encoding:

Scope  (2)

Encode the bytes 1 through 12:

The bytes can be recovered using BaseDecode:

Convert hexadecimal pairs to byte values:

View the individual bytes:

Properties & Relations  (8)

Characters outside the valid alphabet are automatically dropped:

The "Base16" format uses two characters for each byte value:

"Base64" encodes up to three bytes in each block of four characters:

Input must be properly padded to a multiple of four:

"Base85ASCII" can encode four bytes in a block of five characters:

Unlike other formats, padding is not required to yield a complete block:

The character "z" is special and denotes four consecutive zeros:

BaseEncode is the inverse of BaseDecode:

BaseEncode decodes a Base64-encoded string to binary data:

The import format "Base64" decodes a Base64 string and converts the resulting bytes to a string:

Achieve the same result with BaseDecode and ByteArrayToString:

BaseDecode converts the "Base64Encoding" format of Hash to its "ByteArray" format:

ByteArray uses Base64 encoding of its data in InputForm:

Possible Issues  (1)

Base64 inputs must be properly padded to the correct length:

Wolfram Research (2018), BaseDecode, Wolfram Language function, (updated 2020).


Wolfram Research (2018), BaseDecode, Wolfram Language function, (updated 2020).


Wolfram Language. 2018. "BaseDecode." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020.


Wolfram Language. (2018). BaseDecode. Wolfram Language & System Documentation Center. Retrieved from


@misc{reference.wolfram_2024_basedecode, author="Wolfram Research", title="{BaseDecode}", year="2020", howpublished="\url{}", note=[Accessed: 18-June-2024 ]}


@online{reference.wolfram_2024_basedecode, organization={Wolfram Research}, title={BaseDecode}, year={2020}, url={}, note=[Accessed: 18-June-2024 ]}