In a typical apartment project, each unit generally contains between 5 to 10 interior doors, depending on layout and size. A one-bedroom unit usually requires 5–6 doors, a two-bedroom unit 6–8 doors, and a three-bedroom unit 8–10 doors, including bedroom doors, bathroom doors, closet doors, and utility room doors. For a 100-unit apartment building, total interior door demand often ranges from 600 to 800 doors. Exact quantities depend on floor plan design, local standards, and project specifications.