Door Size Calculator – Find Your Opening / Trim Size

Calculate Your Door Trim/Opening Size

Door Size Calculator

Use this calculator to work out the size your opening / trim size needs to be to fit your specified door size. Select from single and double pre hung doors, single and double cavity sliders, double and triple robe makers and 2 & 4 door multi bifolds. Specify your door leaf sizes and jamb type to calculate your opening / trim size.

Note that the height calculation for hung doors allows for a 27.5mm gap under the door. This allows for most carpet + underlay thicknesses, however we suggest checking your chosen flooring thickness will result in the desired gap below door when complete.