The math behind your estimate
The inputs, allowance, and rounding stay visible.
- Volume
- Volume = Length × Width × Depth, summed over all areas
- Weight
- Weight = Volume incl. allowance × density (approximate)
- Bags
- Bags = Volume incl. allowance ÷ bag volume, rounded up
Assumptions
- Densities are approximate: loose dry topsoil ~75 lb/ft³ (1,200 kg/m³), moist ~90 lb/ft³, compacted fill ~105 lb/ft³. Moisture alone can change soil weight by 30% or more.
- Delivered soil is loose and settles roughly 10–20% after watering. For raised beds, plan to top up after the first season.
Frequently asked questions
- How much soil do I need for a raised bed?
- Multiply length × width × depth. A 4 ft × 8 ft bed filled 10 inches deep needs about 27 cubic feet — one cubic yard, or roughly 36 bags at 0.75 ft³. Add each bed as a named area to total a whole garden.
- How much does a cubic yard of topsoil weigh?
- Around 2,000 lb (1 US ton) when loose and dry, and up to 2,700 lb when moist. That's why suppliers cap how many yards fit on a truck — and why the weight here is an estimate, not a guarantee.
- Loose or compacted — which volume am I ordering?
- Suppliers sell loose volume. If your project needs compacted fill (under a path or slab), compacted soil occupies 15–25% less space, so order extra loose volume — increase the allowance to cover it.
- Bags or bulk soil?
- Bags win below roughly half a cubic yard, or where a truck can't reach. Above a yard, bulk is much cheaper per yard. Set 'Buying' to your bag size to see the count, or Bulk to plan a delivery.
Sources
- Typical topsoil/fill bulk densities (landscape supplier reference values)