Room Volume Calculator
Calculate cubic feet and cubic meters of a room from length, width, and height. Useful for HVAC, ventilation, and air purifier sizing.
Assumptions
- Room is a rectangular box.
- Height is floor to ceiling.
- Does not deduct furniture volume.
- Sloped ceilings need average height or segmented calculation.
- Open doorways to other spaces change effective volume for HVAC.
Volume = length × width × height (converted to consistent units).12 × 10 × 8 ft room
- Volume = 12 × 10 × 8 = 960 ft³ ≈ 27.2 m³.
How to measure
Measure length and width on the floor and ceiling height at the center. For vaulted ceilings, measure average height or divide into sections.
Common mistakes
- Using wall height minus baseboard inconsistently.
- Treating whole-house volume as one room without zoning.
- Confusing cubic feet with square feet.
Frequently asked questions
Why does volume matter for HVAC?
Air handlers move air through space. Volume helps estimate air changes per hour.
Air purifier CADR sizing?
Manufacturers recommend CADR relative to room volume and ACH targets.
Open floor plan?
Use combined dimensions of the connected space or size each zone separately.
Metric output?
Cubic meters are shown alongside cubic feet.