How much sand do I need?

The screeded bedding course is normally about 1 inch (25 mm) — and it should stay at 1 inch. Thicker bedding is the usual cause of pavers settling unevenly later, because sand consolidates under load. Depth of the compacted aggregate base underneath is a separate question, and it is usually 4 inches for a patio and more for a driveway.

Coarse, sharp, washed concrete sand is the conventional bedding material because its angular grains lock together. Fine masonry or play sand is too rounded and will keep moving. Polymeric sand is a different product again — it goes in the joints between pavers, not underneath them.

About 1.35 tons per cubic yard for dry building sand. Sand is often sold by the ton rather than the yard, so knowing both figures keeps you from over- or under-ordering when the supplier quotes in the other unit.

Multiply the area by the depth you want. A 6 × 6 ft box filled 10 inches deep needs 36 × 0.83 = 30 cubic feet, a bit over 1 cubic yard. Use washed play sand for that job, not concrete sand.