You can't.
Access uses only the amount of space required. For example, if you have a
field that is of type Text, with the Field Size set to 50, but a particular
record contains only 20 characters, then it uses only 20 characters. That
means that even if you add up the bytes the could be needed for each field
of each record, plus the overhead for each field and each record and the
table itself, you still cannot arrive at an answer.
Further difficulties involved the Unicode Compression setting for each text
field, the fact the BLOB fields such as ,memo, hyperlink, and OLE Object
require pointers and occupy secondary storage, and the inability to know
whether deleted records are occuping space that would be freed if the
database were compacted, and any attempt to calculate the required space
becomes an exercise in futility.
