The cabinet fitting between two walls is only the first sizing test. You also need operating clearance, a path into the room, and a realistic idea of what each load can hold.
Measure the full envelope
Record usable width, depth, and height. Then account for lid or door movement, hoses behind the appliance, faucet reach, airflow clearance, leveling, and the space needed to load and unload safely.
Measure the path, too
A machine that fits the final corner may not fit through the doorway, hallway turn, elevator, or storage opening. Record the narrowest point and include handles, packaging, and safe carrying clearance.
Treat load examples as approximate
Cubic-foot and weight claims are not interchangeable across products. Fabric type, item bulk, balance, and manufacturer loading instructions change what is practical. Bedding is a much harder requirement than everyday clothing.
Leave operating clearance
Published cabinet dimensions do not include every movement and connection. Add room for the lid to open, hoses to bend without kinking, the faucet connection to sit naturally, and your body to load the tub. If the washer will roll into storage, measure both its working position and its storage position.
Translate capacity into frequency
A smaller tub can work well when loads are frequent and predictable. A larger tub may reduce the number of cycles, but it takes more floor space and is heavier to move. Instead of chasing the largest number, estimate how many everyday outfits, towels, and sheets you need to wash between laundry days and choose the smallest model that can handle that routine comfortably.