How to use the Room / House Cubic Feet Calculator
- Use room dimensions within the walls. Split rooms with varying ceilings or L-shaped footprints into simpler sections.
- Enter the room’s inside length, width and ceiling height, choosing a unit for each measurement.
- Select Calculate. Review the result and its working; if you change an input, calculate again before copying or sharing.
Room / House formula
Room air volume is floor area multiplied by a uniform ceiling height, with every length converted to feet first.
Room volume = length × width × ceiling height
What the terms mean
- Room length
- A measured length in the selected unit; it is converted to feet before volume is calculated.
- Room width
- A measured length in the selected unit; it is converted to feet before volume is calculated.
- Ceiling height
- A measured length in the selected unit; it is converted to feet before volume is calculated.
Room / House worked examples
Find air volume for a rectangular room
Measure an unobstructed rectangular room as 12 ft long, 10 ft wide and 8 ft high.
- Floor area × ceiling height
Answer: 960 ft³. Cubic yards: 35.555556 yd³; Litres: 27,184.172728 L; Floor area: 120 ft².
Compare a room with a higher ceiling
A room measures 15 ft × 12 ft with a uniform 9 ft ceiling. Calculate its floor area and air volume.
- Floor area × ceiling height
Answer: 1,620 ft³. Cubic yards: 60 yd³; Litres: 45,873.291479 L; Floor area: 180 ft².
Room / House Cubic Feet Calculator FAQs
Can this size an air conditioner?
No. Equipment sizing also depends on heat transfer, climate, occupancy and other conditions.
What if the ceiling slopes?
Use an appropriate average-height model or split the room into box and triangular-prism sections.
Measurement guide for Room / House
Measure inside wall-to-wall distances and ceiling height. Divide rooms with changing heights or separate alcoves into simpler sections.
Assumptions and limits
Cubic feet alone do not determine heating, cooling or ventilation equipment size. This page reports geometric volume and floor area.
This estimates rectangular air volume. HVAC sizing also depends on heat loss, climate, insulation and occupancy.
Check your result
Multiply the floor-area result by ceiling height to check the air volume. This volume does not by itself size an HVAC system.