It is important to check the dimensions of a wall hung toilet. For instance, if you are buying a toilet for small bathrooms, you should check the smallest wall-mounted toilets on the market. The dimensions of the toilets are usually mentioned in the descriptions, so you should not have a hard time finding one which fits your bathroom well.
You will also need to check the height of the toilet. This factor will affect the usability and comfort of the toilet. Ideally, you should go for a toilet that has an adjustable height.