Each calculator on ComponentCalc is reproducible. The formulas and constants below are what the tools use. Where a value varies in the real world, we say so and use a documented average.
Volume and area
Volume in cubic yards equals area in square feet times depth in feet, divided by 27. In metric, volume in cubic metres equals area in square metres times depth in metres. One cubic yard is 27 cubic feet and about 0.7646 cubic metres.
Concrete bag yields
| Bag | Yield of mixed concrete |
|---|---|
| 80 lb | 0.60 cubic feet |
| 60 lb | 0.45 cubic feet |
| 50 lb | 0.375 cubic feet |
| 40 lb | 0.30 cubic feet |
Metric bags are estimated at about 0.0117 cubic metres for 25 kg and 0.0094 for 20 kg. About 45 of the 80 lb bags make one cubic yard.
Coverage and density
- Mulch and soil: one cubic yard covers 324 square feet at one inch deep.
- Paint: about 350 to 400 square feet per US gallon per coat, or 8 to 10 square metres per litre.
- Crushed gravel: roughly 1.4 tons per cubic yard. Topsoil: roughly 1.1 tons per cubic yard. Both vary with material and moisture.
Waste factors
Defaults added before rounding up: concrete 7 percent, gravel, mulch, topsoil and paint 5 percent, flooring, tile and drywall 10 percent. Diagonal tile and flooring layouts warrant closer to 15 percent.
Why we round up
A shortfall stops a job and a second trip or delivery costs far more than the leftover material. Every result is rounded up to whole bags, sheets or tiles.