Approximately, an official competition dart court roughly takes up 13 to 16 feet. 

The dartboard should hang at a length of 5,67 feet from the ground up with a throwing distance of 7.77 feet cm starting from the oche.

The oche must have a width minimum of 24.01 inch and a 1,49 to 2.36 inch height.

Another important factor is the lightning, which should be mounted in a way where it doesn't cast any shadows on the darts while throwing or landing them in your dartboard.