If you need to know this answer then you may have problems. It should never even be a consideration when designing a kitchen. Sounds like things are too tight.

Here is a kitchen we completed recently. We had tight space to deal with, and so had 36" between the sink counter and the cooktop counter. Still left plenty of room to maneuver around the opened microwave drawer! I would NOT make things any tighter than that!

15" to the inside of the drawer and I agree 36" very, very minimum. 42" - 48" is better. Also, watch for another appliance possibly facing the microwave drawer, like the oven or dishwasher door.

That kitchen is gorgeous thanks for sharing. Our designer has 36 inches spaced in....I'm just second-guessing everything tonight! It is a townhouse kitchen, although a fairly big townhome at around 3800 sq. feet, it's still a townhouse kitchen. Thx to all for the help.