Calculate only if field value is null

[bknight]

I attempted to calculate a value only when the field is null and Ms doesn't like my code.
If Fld5 = Null then
The code skips all records even when they are null values.
So what is the correct coding?

[HansV]

Null is not really a value, but the absence of a value, so you cannot use = Null in a comparison. Use the IsNull function instead:

If IsNull(Fld5) Then

[bknight]

Thanks