What it works out
Enter the length, width and height of a room, pit or slab. You get the volume, the floor area, the gross wall area and the surface area. Wall area covers all four walls with no deduction for doors or windows, and surface area is the walls plus the floor, with no ceiling. This is pure geometry: it adds no waste and is not an order quantity.
You enter
- Length
- Width
- Height
The formula
- Volume
- length × width × height
- Wall area
- 2 × (length + width) × height
- Floor area
- length × width
In words: Volume = length times width times height; wall area = 2 times (length plus width) times height; floor area = length times width
Worked example
A room 10 ft by 20 ft with 8 ft walls
- Length 10 ft
- Width 20 ft
- Height 8 ft
- Volume = 10 × 20 × 8 = 1600 ft³
- Floor area = 10 × 20 = 200 ft²
- Wall area = 2 × (10 + 20) × 8 = 480 ft²
- Surface area (walls plus floor) = 480 + 200 = 680 ft²
Volume in cubic yards: 1600 ÷ 27 = 59.26 yd³.
Good to know
- No deduction for doors or windows in the wall area.
- Surface area has no ceiling.
- Not an order quantity: no waste is added.
- A calculator, not a building-code check: confirm local rules with your building authority.
Questions
Does wall area subtract doors and windows?
No. It covers all four walls in full. Subtract openings yourself.
Can I get cubic yards?
Yes. Choose the result unit; 1 yd³ is 27 ft³.