Typical spacing is 15-18 inches. You may want to consider the size of your appliances you would like to place under the wall cabinets to determine the height of this spacing.

I agree with M Miller. 18" is standard and manufacturers of small appliances use that standard to design their appliances.

Another thing to factor in -- light rail. If you plan light rail, you might want to consider 18" + the height of your light rail. That way, taller small appliances will still fit.

I wish we had done that. We planned for 18", not realizing the light rail would take away from our usable height. (No, our KD did not mention it.) My KA stand mixer (bowl lift) actually brushes the light rail when I slide it in/out from under the cabinets. I have a cover for it and I have to take the cover off b/f I can slide it past the light rail.

18” is standard. We asked for 20”-21” because we’re tall and our cabinets are to the ceiling, and we’ll have plug molds and under cabinet lighting.

@Kristen E. - (sorry to go OT from the OP), I don't know if you are only installing plugmold, and installing no outlets in the backsplash or not. But just in case, please read this thread:

Thread about hiding kitchen cords with when you have plugmold

Thanks, Shannon; I’ll take a look!

I did like Kristen E - mine are 20.5" off the counter. We installed plugmold at the rear and UC lights about 2" from the fronts of the uppers. Yes, you can see cords, but no, it doesn't bother us.

I really like the extra height. My previous cabinets were 15" off the counters and many appliances would not fit. Plus it just felt and looked cramped. The 20-21" height, if you don't mind them a couple inches higher than normal, looks really spacious to me.

We did plugmold along our cooktop wall b/c nothing on that wall is kept plugged in. However, we did outlets on the sink wall b/c I knew the TV and Cable box would be constantly plugged in. It turns out it was a good thing we did it on both sides of the sink, b/c my DH has recently started drinking coffee and we now have a coffeemaker plugged in all the time!