The storage that is needed for each type is determined by the length of the string.
String Types
Type NameMax Size
CHAR(X)255 bytes
VARCHAR(X)255 bytes
TINYTEXT255 bytes
TINYBLOB255 bytes
TEXT65535 bytes
BLOB65535 bytes
MEDIUMTEXT1.6MB
MEDIUMBLOB1.6MB
LONGTEXT4.2GB
LONGBLOB4.2GB