The average height of an otr microwave oven is about 17.
Standard over the stove microwave size.
Typical over the range microwave under 30 kitchen cabinet might have an actual width 29 1 2 29 3 4 29 7 8 29 15 16 or precise 30.
13 distance is the minimum you should aim for.
The more the merrier.
The following dimensions are typical for over the range microwaves based on a study of popular models available from major manufacturers.
These units range in width from 21 to 29 inches.
Over the range microwave average size and dimensions the typical external microwave dimensions of an over the range microwave are 30 inches wide 15 inches tall and 16 inches deep although they can vary as they need to fit into specific cabinet spaces.
Most models have a width of between 29 and 30 inches a depth of between 15 and 16 inches and a height of between 16 and 18 inches.
Internal capacities of over the range models range from 1 to 2 cubic feet.
Therefore considering the earlier measurements discussed in point 1 above you will have about 13 of distance left between the cooktop and the bottom of the otr microwave oven.
Typical dimensions over the counter microwave 24 x 14 x 16 width height depth and 1 5 cubic feet capacity.
Note that they are organized by capacity.