Material Calculators for Concrete, Gravel, Mulch & Soil
Work out how much concrete, gravel, mulch or soil to buy. Enter your area and depth and get cubic yards, cubic feet and bag counts, with the formula shown.
Calculators by material
Concrete calculators
Slabs, footings, post holes and bag counts for 40, 60 and 80 lb mixes.
Gravel & rock
Cubic yards and tons for driveways, paths, pea gravel and river rock.
Mulch
Yards or bags of mulch for beds of any shape and depth.
Topsoil & fill dirt
Topsoil, fill dirt and raised-bed soil by the yard.
Sand & pavers
Paver base, bedding sand and paver counts for patios.
Unit converters
Cubic feet ↔ cubic yards, yards ↔ tons, square feet to yards.
How deep should each material be?
Depth drives the order more than area does: going from 2 in to 3 in of mulch adds half again as much material. Typical depths for common projects, and what they mean per 100 square feet:
| Material and use | Typical depth | Per 100 ft² |
|---|---|---|
| Concrete patio or walkway | 4 in | 1.23 yd³ |
| Concrete driveway | 6 in | 1.85 yd³ |
| Gravel path | 3 in | 0.93 yd³ |
| Gravel driveway (all layers) | 6 in | 1.85 yd³ |
| Mulch in garden beds | 3 in | 0.93 yd³ |
| Topsoil for a new lawn | 4 in | 1.23 yd³ |
| Raised bed soil | 12 in | 3.70 yd³ |
| Sand under pavers | 1 in | 0.31 yd³ |
Typical ranges for planning. Base layers, soil type and local code can change the right depth for your job.
How we calculate
Every calculator uses the same three steps, and each page shows its exact formula:
- Volume. Length × width × depth, with depth converted from inches to feet (÷ 12).
- Cubic yards. Cubic feet ÷ 27, because one cubic yard is 3 ft × 3 ft × 3 ft.
- What to buy. Bags are always rounded up. Bag yields come from the manufacturer's data sheet, not from estimates.
10 ft × 10 ft × (4 in ÷ 12) = 33.33 ft³ ÷ 27 = 1.23 yd³