Garden Bed Soil Calculator

Loose bulk densities from the US EPA Standard Volume-to-Weight Conversion Factors table.
Overrides the table density. A supplier ticket in tons per cubic yard divides by 27 and multiplies by 2000 to give lb/ft3.
Typical spreads: 2-3 in of mulch, 3-4 in of decorative stone, 4-6 in of driveway gravel, 4-6 in of new topsoil.
Loose delivered gravel loses roughly 10-20% of its volume when compacted into a base.
Raised beds and garden beds are normally filled with a blend rather than one material. Set the share below.
By volume. 0 means a single material. A common raised-bed fill is roughly a third compost by volume.
Volume
0.7901 yd3
Gravel, Soil and Mulch Calculator
Area covered
32.00 ft2
Area covered
3.556 yd2
Area covered
2.973 m2
Depth
8.000 in
Volume
21.333 ft3
Volume
0.6041 m3
Order this much (rounded up to the half yard)
1.00 yd3
Bulk density used
67.16 lb/ft3
Weight
1,433 lb
Weight
0.716 ton (US short)
Weight
0.650 t (metric)
Weight
649.9 kg
Bags needed
15
Order this much (rounded up to the half ton)
1.0 ton (US short)
Base material in the blend
0.5531 yd3
Blended-in material
0.2370 yd3
One cubic yard covers
40.50 ft2
Worked out from U.S. EPA, Standard Volume-to-Weight Conversion Factors (loose bulk densities for gravel, sand, stone, soil, wood chips and compost) and 3 other sources.
No compaction allowance was applied. Loose gravel and crushed stone lose roughly 10-20% of their volume once compacted into a base.
Moisture content moves bulk weight substantially. Wet sand and gravel can be 20-30% heavier than the dry figures above.

How this is worked out

7 steps
  1. Area = 8 ft x 4 ft = 32 sq ft
  2. Depth = 8 in = 0.66667 ft
  3. Volume = 32 x 0.66667 = 21.3333 cu ft = 0.7901 cu yd
  4. Density = 67.164 lb/ft3 (70% EPA table: Soil/sandy loam, loose - 1 cubic yard - 2,392 lb (Tellus); 2392/27 = 88.593 + 30% EPA table: Compost, loose - 1 cubic yard - 463.39 lb (Tellus); 463.39/27 = 17.163)
  5. Weight = 21.3333 x 67.164 = 1432.8 lb = 0.716 US short tons
  6. Blend split: 0.5531 cu yd of the base material plus 0.237 cu yd blended in (EPA table: Compost, loose - 1 cubic yard - 463.39 lb (Tellus); 463.39/27 = 17.163)
  7. Bags = ceil(21.333 cu ft / 1.5 cu ft) = 15

Results are general information, not financial, tax, legal, medical or engineering advice.