Our storage units are generally 14ft high, except the 12X10 units, those are 9ft high. If your looking to get the cubic volume of the unit, multiply the square footage by 14. For example, a 10'x10' storage unit, which is one of the most popular unit sizes, has a total volume of 1,400 cubic square feet. Calculating the total volume of a storage unit helps you better understand how much stuff you can actually store.