Sizes of baby stroller accessories vary based on which type of accessories you will be getting. Accessories that provide head and neck support measure around 9 inches long, 6.5 inches wide and 2.2 inches deep. Generally however, the sizes are universal which means that they will fit most standard-sized baby strollers.
Sizes of baby strollers depend on whether you will be getting a single stroller or a double stroller. Single strollers are usually around 40 inches long by 27 inches high by 15.8 inches wide. Double strollers that are side-by-side are approximately 39.2 inches long by 33.2 inches high by 29.8 inches wide while tandem strollers are about 52 inches in length by 40.2 inches in height by 25.5 inches in width.