Table lookups for interpolation

I've been scratching my head over this for a while, so I'm hoping someone could point me in a new direction. I've got a table for engine power settings with temperature down the left and altitude across the top. I can use hlookup and vlookup to find the next highest values, but what I need to be able to do is find power settings for the next higher AND lower temperatures and next higher AND lower altitudes so that I can interpolate for the correct power setting.

Any thoughts would be most appreciated.

Very cool! Thanks!!

JRQ

You're welcome.

I hadn't looked at this in a while, and posted an update after you saw it. Returns the same results, a little cleaner internally.