Maybe this?

http://people.stfx.ca/bliengme/Excel...UnderCurve.htm

--
Kind regards,

Niek Otten
Microsoft MVP - Excel

"Zurich" wrote in message
...
When experimental data describe a 2-dimensional curve which is more
complex
than can be fit by a 6th degree curve-fit estimate, Excel is still capable
of
filling the area with colored pixels when using the Area chart wizard. The
area of those pixels is exactly what is needed: How can a person
accurately
determine that area?