The rule is already written on our dumpsters
Kitchens and bathrooms are the most common indoor renovations, and the size question comes back every time. The answer is already written into our size cards, and even into our quote form.
Bathroom alone: the 10 cubic yard is often enough. The box is 14 ft long by 8 ft wide and 2.5 ft high — the equivalent of 3 to 4 pickup truck loads. A bathroom is a small room, but a dense one: the tub and the ceramic tile add up fast in weight, and a low box loads by shovel without pushing past the truck's limit.
Kitchen — or kitchen and bathroom done together: the 20 cubic yard. Same footprint on the ground, 5 ft high, 6 to 8 pickup truck loads, about the size of a Dodge Caravan. Our quote form spells it out right next to the size: “kitchen + bathroom”. It is our most requested size. One nuance: a small kitchen on its own can fit a 10 yard — the example listed next to the small size.