Depends on what kind of equations describe the 2 series.

If they are 2 straight lines:
y = a1 + b1*x
y = a2 + b2*x
Then you can algebraically solve to see that they intersect at
x = -(a1-a2)/(b1-b2)

For non-linear equations, use Solver.

Jerry

mic wrote:

how to find interception point from a grahp with 2 series of data in Excel