How to Calculate Room Volume in Cubic Feet
Calculating the volume of a room or space in cubic feet is straightforward:
Volume (ft³) = Length (ft) × Width (ft) × Height (ft)
From inches: (L" × W" × H") ÷ 1,728 = ft³
From metres: m³ × 35.3147 = ft³
From inches: (L" × W" × H") ÷ 1,728 = ft³
From metres: m³ × 35.3147 = ft³
Example: A living room 18ft long × 14ft wide × 9ft high = 18 × 14 × 9 = 2,268 ft³
Common Uses for Cubic Feet in Home & Garden
| Application | What You're Calculating | Use Result For |
|---|---|---|
| Storage Unit | Unit L × W × H (ft) | Choosing the right unit size |
| Moving Truck | Truck interior volume (ft³) | Booking the right truck size |
| Firewood / Mulch | Stack L × W × H (ft) | Ordering correct cord quantity |
| Air Conditioning | Room volume (ft³) | Sizing BTU/ton capacity |
| Garden Soil / Topsoil | Bed L × W × depth (ft) | Ordering bags or bulk delivery |
| Aquarium | Tank L × W × H (ft) | Water volume in gallons |
| Concrete Slab | L × W × thickness (ft) | Ordering cubic yards of concrete |
Cubic Feet to Other Units
| 1 Cubic Foot = | Value |
|---|---|
| Cubic Metres (m³) | 0.028317 m³ |
| Cubic Inches (in³) | 1,728 in³ |
| US Gallons | 7.481 gallons |
| Litres | 28.317 L |
| Cubic Centimetres | 28,316.8 cm³ |
Storage Unit Size Guide
Use this reference to pick the right storage unit for your needs:
| Unit Size | Volume (ft³) | Fits Approx. |
|---|---|---|
| 5×5 ft (8ft ceiling) | 200 ft³ | Small bedroom contents, boxes |
| 5×10 ft | 400 ft³ | 1-bedroom apartment |
| 10×10 ft | 800 ft³ | 2-bedroom apartment |
| 10×15 ft | 1,200 ft³ | 3-bedroom house |
| 10×20 ft | 1,600 ft³ | 4–5 bedroom house + vehicle |
Frequently Asked Questions
A standard 12×10 ft bedroom with 8ft ceilings = 960 ft³. A master bedroom (14×12 ft) = 1,344 ft³. These figures are used for HVAC sizing — the common rule is 1 ton of AC capacity per 400–600 ft² (multiply by ceiling height for ft³).
Divide cubic feet by 27 to get cubic yards. Concrete is typically ordered in cubic yards. A 4-inch thick slab (0.33 ft) that is 20×10 ft = 66 ft³ ÷ 27 = 2.44 cubic yards. Always order 10% extra for waste.
Calculate: length × width × depth in feet. For a 3-inch (0.25 ft) layer over a 10×8 ft bed = 20 ft³. Mulch is sold in 2 ft³ bags, so you'd need 10 bags. For bulk delivery, 1 cubic yard = 27 ft³.
Use this guide: 10ft truck (~400 ft³) = studio/1-bed, 15ft truck (~800 ft³) = 2-bed apartment, 20ft truck (~1,100 ft³) = 3-bed house, 26ft truck (~1,700 ft³) = 4–5 bed house. Add up your furniture volumes using this calculator to pick the right size.