When trying to determine how big of a conference table you need, first, measure the room. If the room is 20 feet long then you need to deduct approximately 3 feet from either end. This will give you room for a chair at either end plus some walking room if a person is seated at the table. Based on those measurements you should be able to fit between a 12ft. and 14ft. table. If you would like to have a credenza at one end of the room then it would be better to go with a 12ft. long table. Stop by C.J. Office Furniture TODAY to see how we can help you maximize your space.