VBA / User Defined Function for an Antiparallel SUMPRODUCT

[GrahamJD]

I had something like this built years ago, but now I need it again and don't have the original code
Function has two range variables: rng1 and rng2
Function output is the sum of the 1st value in rng1 times the last value in rng2, through to the last value in rng1 times the first value in rng2.
E.g. If the ranges had 1,2,3 and 4,5,6 respectively then the calculation would be 1*6 + 2*5 + 3*4 and the output would be 28. Note: Normal SUMPRODUCT function would give 1*4+2*5+3*6=32
I should confirm both ranges have the same length, and I should be able to use a For Each cell in..., but I'm not seeing how to reference the opposing cell in rng2.
Any suggestions welcomed.

[Norie]

Perhaps.

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[GrahamJD]

Thank you Norie!
With a little tweak or two it is working great!

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[MickG]

Try :-

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