[header] How to build a dog box [title] Determine how much space your dog needs. [step] Make sure your dog has adequate room inside the box to be comfortable. Measure your dog to determine the minimum height, width, and depth that your box needs to be. 
Give your dog enough room to lie down and shift position without the box taking up unnecessary space in your vehicle or living space. [substeps] For height, have your dog sit on its rear legs.