▁standard ▁door ▁sizes ▁in ▁the ▁US ▁run ▁along ▁ 2 " ▁incre ments . ▁Custom ary ▁sizes ▁have ▁a ▁height ▁of ▁ 7 8 " ▁( 1 9 8 1   mm ) ▁or ▁ 8 0 " ▁( 2 0 3 2   mm ) ▁and ▁a ▁width ▁of ▁ 1 8 " ▁( 4 7 2   mm ), ▁ 2 4 " ▁( 6 1 0   mm ), ▁ 2 6 " ▁( 6 6 0   mm ), ▁ 2 8 " ▁( 7 1 1   mm ), ▁ 3 0 " ▁( 7 6 2   mm ) ▁or ▁ 3 6 " ▁( 9 1 4   mm ). ▁Most ▁resident ial ▁passage ▁( room ▁to ▁room ) ▁doors ▁are ▁ 3 0 " ▁x ▁ 8 0 " ▁( 7 6 2   mm ▁x ▁ 2 0 3 2   mm ). ▁ ▁A ▁standard ▁US ▁resident ial ▁( ex terior ) ▁door ▁size ▁is ▁ 3 6 " ▁x ▁ 8 0 " ▁( 9 1 ▁x ▁ 2 0 3   cm ). ▁Inter ior ▁doors ▁for ▁wheel ch air ▁access ▁must ▁also ▁have ▁a ▁minimum ▁width ▁of ▁ 3 '- 0 " ▁( 9 1   cm ). ▁Res ident ial ▁interior ▁doors ▁are ▁often ▁somewhat ▁smaller ▁being ▁ 6 '- 8 " ▁high , ▁as ▁are ▁many ▁small ▁stores , ▁offices , ▁and ▁other ▁light ▁commercial ▁buildings . ▁Lar ger ▁commercial , ▁public ▁buildings ▁and ▁grand ▁homes ▁often ▁use