Evert,

With your X-values in A1:A11, and your Y values in B1:B11, the formula

=SUMPRODUCT((B2:B11+B1:B10)*(A2:A11-A1:A10))/2

with return the trapezoidal approximation of the area under the curve.

Obviously, the smaller the interval of your X values, the better the resolution of the
approximation.

HTH,
Bernie
MS Excel MVP


"Evert" wrote in message
...
I'm trying to calculate the area of a graph (data series) between the x-axis
and the data-series in excel 2002. I don't know how. Please help!