These hand forged door hinges are designed to work with heavy oak doors. As a rough guide the length of the hinge we recommend can be determined as 1/2 to 2/3 of the total door width. So for example if your door is 33' wide you would calculate it as follows: 33 x 0.5 = 16.5' would be the minimum size hinge, so go for the 18' version. If your door was under the stairs and only 24' wide a 12' hinge would do the job. Of course if your doors are light-weight for example pine; you may get way with smaller hinges than we suggest. For an authentic look though always stick to the 1/2 to 2/3 rule.