Yes. On a report, you can place a calculated control that counts (Count function) the number of instances of any one field that can't be Null. Such a control has to be in a header or footer in the main or grouping section. Or this control can use the Running Sum feature over group, or over all as long as (I think) you don't use it on a numerical value. In that case I'd expect 10 and 20 to result in 30 and not a count of two.
In a query, you can also use the Count function to create a calculated field although the number returned will appear in each record. You could also use a separate Totals query that gets the count of said field. Then there is the DCount function, which will return the number of records in a table or query according to criteria you include in the function syntax. A form or report control can use Dcount as its source.