What is the standard thickness of most interior passage doors?

The standard thickness of most interior passage doors is 1-3/8 inches. This measurement has become the industry norm because it provides a good balance between strength, stability, and insulation. Doors at this thickness are adequately robust for everyday use, yet still lightweight enough for ease of operation.

Additionally, this thickness allows for compatibility with standard door frames and hinges, ensuring a proper fit in most residential settings. Thicker doors, such as those measuring 2 inches, are typically reserved for exterior doors or specialized applications where enhanced durability and security are required. Consequently, interior doors generally adhere to the 1-3/8-inch standard, making this option the right choice for most residential construction projects.