If you have 96" high ceilings typically soffit dimensions are 84" from the floor to the bottom of the soffit.  Soffits are typically 14" in depth and 12"in height. From the top of the counter top to the bottom of your wall cabinets there should be 18" of space, to allow for appliances etc.

Remember to take measurements of windows, doors and any other wall obstacles. Measure widths, heights (Trim to Trim) and their locations on walls. You can only install cabinets on blank wall space. Also take note of electrical and plumbing fixture locations, in you are planning to reconfigure you kitchen layout. If reconfiguring your Kitchen or bath these fixtures may have to be moved.

NOTE: There are exceptions to every rule. These measurements are design standards. Distances between counter tops and wall cabinets can vary depending on how level your floor is, how square, level and plumb your walls and ceilings are.