How this calculator works
Rounded stones leave spaces between particles. The default 1800 kg/m3 is a clearly identified clean-stone reference, not a measured value for every river-rock blend. Replace it with the supplier bulk density; use the stated depth of the finished layer.
Formula
A = L x W, pi x D^2 / 4, b x h / 2, or (front + back) x h / 2; Vnet = A x depth; Vorder = Vnet x (1 + waste); mass = Vorder x density; cost = tonnes x rate or Vorder x rate, plus fixed charges.
Worked example
A 4 m2 bed at 0.25 m deep holds 1 m3. At a supplied 2000 kg/m3 it takes 2000 kg before waste.
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Frequently asked questions
Can I use solid granite density?
Not for a loose bed. Solid rock density omits the spaces between pieces and will normally overestimate the mass per bed volume.
How do I price a cubic-yard quote?
Convert the quote to dollars per cubic metre before using volume pricing. One cubic yard is 0.764554857984 m3.
Is the result a bag count?
The result is mass and volume. Divide mass by the printed net mass of a bag and round up; decorative bags vary by supplier.