Methodology
Every calculator turns your measurements into an area in square feet, multiplies by depth for a volume, and converts to the units suppliers sell: cubic yards, tons, bags or pallets.
Cubic feet = area (sq ft) × depth (in) ÷ 12. Cubic yards = cubic feet ÷ 27. A circle's area is π × (diameter ÷ 2)².
Bag counts always round up. The "extra for waste" percentage is added to the area before anything else, to cover uneven ground, settling and cuts.
Standard figures
| Material | Figure used | Sold as |
|---|---|---|
| Mulch (shredded hardwood) | Sold by volume | 2 and 3 cu ft bags |
| Topsoil | about 1.0–1.3 tons per cu yd (we use 1.1) | 0.75 and 1 cu ft bags |
| Gravel and crushed stone | about 1.3–1.5 tons per cu yd (we use 1.4) | 0.5 cu ft bags |
| Concrete mix | 80 lb bag ≈ 0.60 cu ft; 60 lb ≈ 0.45; 40 lb ≈ 0.30 | Ready-mix sold by the cu yd |
| Sod | Piece 16 × 24 in ≈ 2.67 sq ft | Pallet about 400–500 sq ft (we use 450) |
Each calculator page lists any further assumptions it makes. Weights vary with moisture and particle size, so check your supplier's figure when ordering by the ton.
Corrections
Spotted an error? Email [email protected] and we'll fix it.