Can You Put a Toaster Oven on Top of a Microwave?

The short answer

No. Not because it will certainly catch fire, but because both appliances publish requirements that the stack breaks, and they do it independently of each other — so you end up operating two appliances outside their stated installation conditions, which is also the configuration a warranty claim is assessed against.

The microwave publishes a clearance it needs aboveitself. LG's countertop microwave guidance is to “keep a minimum clearance distance of 20 centimeters from the top” and 10 centimetres from the left, right and back, and separately to “avoid placing heavy objects… on top of microwave oven” and “do not install in an enclosed cabinet.” A toaster oven on the lid occupies precisely the 20 centimetres the manufacturer reserved — and a countertop oven is a heavy object by any reading, at 12 pounds for the BLACK+DECKER TO3250XSB.

The toaster oven publishes the complementary rule from its side. BLACK+DECKER's manual warns against placing “any item on top of unit when in operation”, tells you to “select a location… allowing enough space from back of the unit and the wall to allow heat to flow without damage to cabinets and walls”, and states “do not place on or near a hot gas or electric burner, or in a heated oven.”

Why the microwave's clearance is not optional

A microwave's magnetron and transformer generate waste heat, and a countertop microwave sheds it through ventilation openings in its own cabinet — commonly on the top and sides. The published clearance is not about the food getting hot; it is the air path that keeps the electronics inside their rated temperature.

Block it and the failure is slow rather than dramatic: the components run hotter, for longer, every time the microwave is used, which shortens their life. Manufacturers across the category say some version of this — that restricting airflow leads to overheating and shorter component life — and the published figures vary considerably by brand and model, from a couple of inches on some to 20 centimetres on LG's. Read your own microwave's number; this is one of the cases where brands genuinely disagree.

Now add the second problem. A toaster oven is not an inert object sitting in that gap — it is a heat source. BLACK+DECKER rates its exterior as hot enough to require mitts on any outer surface, and extends its flammable-material warning to the oven “when in operation or after, when still hot”. So the appliance you have put in the microwave's cooling path is actively warming the air that was supposed to carry heat away. That is the stack's real flaw, and it is why “I left a two-inch gap” does not resolve it.

The toaster oven's own problem with the arrangement

Looked at from above, the stack is bad for the oven too, in three published respects.

It is not a flat, stable, heat-tolerant surface. A microwave lid is sheet metal or plastic over a cavity, often slightly flexible and rarely perfectly level. A countertop oven that rocks is a countertop oven whose door can swing and whose contents can slide — and whose feet, which exist to hold the hot base off the surface, may not all be in contact.

It raises the oven. Stacking typically puts the oven door at or above eye level, which means reaching up and over a hot cavity to take out a hot tray. That is the exact ergonomic hazard our seniors ranking is built around, and it applies to everyone with a heavy casserole.

It usually puts the oven under a cabinet.Two appliances stacked are roughly 20 inches tall, which on a standard kitchen wall brings the top of the oven close to the cupboards — directly against the manual's instruction to allow heat to flow “without damage to cabinets and walls”and against the fire warning about the oven touching “curtains, draperies, walls and the like”. What each maker requires around its own oven is here.

What about the other way round?

Putting the microwaveon top of the toaster oven is worse, not better. The oven is then venting its heat directly into the microwave's underside and the microwave's rear vents, the oven's door opens downward into your knees, and nearly every toaster oven manual we have read prohibits placing any item on top of the unit during operation. If one has to sit above the other, neither manufacturer sanctions it.

The adjacent question people ask next — whether a toaster oven can go in a cabinet, an appliance garage, or on a quartz or wood worktop — comes down to the same two published requirements: free airflow around the box, and a flat heat-tolerant surface under it. The enclosure cases are the hardest no of the group, because they remove the airflow entirely.

What to do instead

Go side by side and buy the depth back. This is the only arrangement both manuals sanction, and it is more achievable than it sounds because the small ovens in this catalog publish genuinely small footprints: the Our Place Wonder Oven at 11.5 inches wide by 10.6 deep, the BLACK+DECKER TO1785SG at 11.22 by 11.54. Either sits beside a microwave in the space a wide oven would have taken alone.

Or go vertical with the oven, not with the stack. The flip-away Ninja ovens publish vertical storage, so the oven leaves the counter between uses instead of occupying a permanent footprint.

Or use a shelf unit rated for appliances, with the published clearance for each appliance on its own shelf — which is a different thing from resting one on the other, because each keeps its own air path.

If you only have room for one, the honest comparison is worth reading before you buy a second appliance at all: toaster oven versus microwave goes through what each genuinely does better, and the small-footprint ranking covers the ovens that fit a counter that already has a microwave on it.