Over-the-Range Microwave Dimensions and Clearance

An over-the-range (OTR) microwave is built to a near-universal ~30″ width so it drops into a standard cabinet opening and replaces the hood. The numbers that actually decide the install aren’t the box size — they’re the clearance above the cooktop and the mounting height.

Standard OTR microwave size

Widths are standardized to match 30″ cabinetry; height and depth vary a little by model and by how far the door and handle project.

Clearance above the cooktop — the number that matters

This is the figure that fails inspections and singes plastic. The widely cited minimum is 30″ from the cooking surface to the bottom of the microwave. Many OTR units are specifically listed for installation as low as 13–18″ above the cooktop — but only those models, and only per their own instructions.

The cabinet opening it needs

OTR microwaves mount to the rear wall and the cabinet above. Plan for a 30″-wide cabinet above the range, with the top of the microwave typically around 66″ from the finished floor (so the bottom clears the cooktop by the required gap). The cabinet above is usually shortened to 12–18″ to make room.

Venting: recirculating vs ducted

Because it replaces the hood, an OTR microwave handles ventilation one of two ways: ducted (out through the wall or roof — the better option) or recirculating (filtered and pushed back into the room). The unit’s CFM is lower than a dedicated range hood, so for serious cooking a separate hood is worth considering.

Measured from official ENERGY STAR data + manufacturer spec sheets · Last verified June 2026