Always use digits and spell out the unit of measurement: 2 meters; 11 inches

Express height in X-foot-X format when used as an adjective: 6-foot-9; 7-foot

Include hyphens when used as a noun: a 7-footer; a 2-miler

Do not include hyphens for adjective descriptors that do not come before a noun: A football field is 100 yards long; He stood 6 feet tall; The pitching rubber is 60 feet, 6 inches from home plate.