What are standard interior door widths?

Interior door 80"

Exterior door - outswing 81"

Exterior door - inswing 80"

Check with your local building supply store before you begin to frame in your door, to verify the sizes that they have in stock.

>>> These are the actual "door slab" sizes. You're probably asking because you want to replace it. If you are, you need to measure the inside diameter of the jams where the door fits within - don't assume. Many doors of these sizes are up to a half inch smaller due to proprietary fitting (sealing and weatherstripping allowances / beveled jams and sills / even shifting or settling...). If you are replacing the whole door and jam - a 'pre-hung' (which I always recommend - especially on exterior doors) - you need to measure the rough opening of the studs behind the molding. Remove the interior trim and remove, or push in, any insulation. Take measurements in a few places (top bottom left right) and both diagonals, to check for square (every house can settle).

Good luck

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