How Much Sand for 400 Square Feet

The 324 is not a fudge factor. A cubic yard is 27 cubic feet, and a foot is 12 inches, so a cubic yard spread one inch deep covers 27 × 12 = 324 square feet.

Depth scales the answer in a straight line, so the whole range fits in one table. Type any depth into the form above to work it out in full. The last column is the coverage of a single unit of volume, which is the number to keep in mind when a supplier quotes by the cubic yard.

Volume is the exact half of this page; weight is the approximate half. Only the top of the band has a source: the WSDOT Design Manual puts material that is essentially all sand at 3,400 lbs per cubic yard compacted. Loose sand, which is how it arrives on a truck, is lighter — and WSDOT publishes no truck-measure figure for sand, so 2,800 lbs is our own allowance rather than a quoted number.

The 10% is quoted, not invented: the WSDOT Design Manual tells estimators to increase required quantities by 10% to allow for waste when material is stockpiled. A screeded sand bed also loses depth once it is compacted. Bagged sand is usually sold by weight, so divide the 3,444–4,182 lbs by the weight printed on the bag — and remember that band is wide, so it gives you a range of bag counts, not one number.