Enter the furniture size, the doorway size, and the space it has to land in — and get a clear fits / does not fit answer for each.
Through a doorway, a piece of furniture can be turned, so the check tests every orientation: some pair of the piece's three dimensions must fit inside the door opening (with the clearance entered), while the third dimension points through the doorway. In its final space the piece normally sits upright, so the check tests the footprint in both rotations — width-by-depth and depth-by-width — against the space. Tight hallways, corners and stairs can still block a piece that passes both checks, so measure turns as well as openings.
What is the standard interior door size? Most interior doors are 30 to 32 inches wide and 80 inches tall; exterior doors are commonly 36 inches wide. Measure the clear opening with the door open, including stops and hinges, not the slab size.
A sofa is longer than the doorway is tall — can it still fit? Often yes. Sofas are usually moved on end or tilted, so the depth and height go through the opening and the length points along the hall. The orientation check here covers that case.