Make sure you have excel in automatic calculation mode.

And make sure that your function gets all its ranges passed to when you write
the formula in the cell.

=myFunc(a1,a2,a3)

Option Explicit
Function myFunc(Rng1 as range, rng2 as range, rng3 as range) as double
dim myTot as double
mytot = 0
if isnumeric(rng1.value) then
mytot = mytot + rng1.value
end if
if isnumeric(rng2.value) then
mytot = mytot + rng2.value
end if
if isnumeric(rng3.value) then
mytot = mytot + rng3.value
end if
myFunc = mytot
End function

Not...
=myFunc2(a1)

Option Explicit
Function myFunc2(Rng1 as range) as double
dim myTot as double
mytot = 0
if isnumeric(rng1.value) then
mytot = mytot + rng1.value
end if
if isnumeric(rng1.offset(1,0).value) then
mytot = mytot + rng1.offset(1,0).value
end if
if isnumeric(rng1.offset(2,0).value) then
mytot = mytot + rng1.offset(2,0).value
end if
myFunc2 = mytot
End function

Excel only knows when to recalc the myfunc2 with the first cell changes--not
when A2 or A3 change.

Worst still, you won't/shouldn't be able to trust the results unless you look
right after a recalc.


Falcon Feet wrote:

I created my own Excel worksheet function in VBA. The function (formula)
works correctly when entered in a cell, but it does not recalculate when the
cell that the formula references changes. FYI, the workbook's "Calculation"
option IS set to Automatic.

--

Dave Peterson