Sand Calculator

How much sand an area needs

Sand is bought by volume and delivered by weight, so «how much do I need» starts as a volume question: area times depth. In imperial units the whole thing collapses into one number:

That 324 is exact and worth knowing on its own. A cubic yard is 3 × 3 × 3 = 27 cubic feet; spread one inch — a twelfth of a foot — deep, those 27 cubic feet stretch over 27 × 12 = 324 square feet. So a cubic yard covers 324 ft² at 1 inch, 162 ft² at 2 inches and 81 ft² at 4 inches. Nothing about sand enters this part of the calculation, which is why the volume answer is exact and the weight answer further down is not.

Step by step

1. Measure the area in square feet. Width × length for a rectangle; split anything L-shaped into rectangles and add them up.
2. Decide the depth in inches. This is your decision, not the calculator's — a bedding course, a play area and a base layer are nothing like each other.
3. Multiply and divide by 324. Area × depth ÷ 324 gives cubic yards; area × depth ÷ 12 gives cubic feet if you are buying in bags.
4. Add about 10% for waste. Quoted from the WSDOT Design Manual, and it also absorbs the depth a screeded bed loses when it is compacted.

How much one cubic yard covers

Sand goes down thin, so the coverage numbers are large and the volume numbers are small — this is the table that keeps an order from being an order of magnitude out. The middle column is the coverage of a single cubic yard; the right column is what 100 square feet would take at that depth.

Common areas and what they take

Every row here has its own page with the depth table, the weight and the ordering figure worked out. All of them assume 1 inch.

What sand weighs — and the one distinction most calculators skip

The WSDOT Design Manual (M 22-01.23, September 2024, Exhibit 620-1) notes in a footnote that where the grading contains more than 45% sand the unit weight approaches 3,400 lbs per cubic yard for material that is essentially all sand. That figure is for compacted sand.

What arrives on a truck is not compacted, and it is lighter for the same volume. WSDOT does not publish a truck-measure weight for sand, so we have no sourced number for it — but the same table does publish both states for gravel: 2,850–3,100 lbs per cubic yard as delivered against 3,400–3,800 compacted, a gap of roughly 20%. We apply that same allowance and print 2,800–3,400 lbs per cubic yard, with 2,800 lbs flagged as our estimate rather than a quoted figure. Most calculators print one number around 2,700 and never say which of the two states it is.

How much to order, and in what

• Bulk, by the cubic yard. The figure this page gives you. Add the 10% and round up to whatever increment your supplier delivers in.
• Bulk, by the ton. Sand yards often quote by weight. Use the weight band and ask which state it is quoted in — the compacted and loose figures differ by about a fifth, and that is a fifth of your bill.
• Bags. Bagged sand is normally sold by weight, so divide the weight band by the weight on the bag. Because the band is wide, you get a range of bag counts rather than a single number — round up.
• The 10% itself. «If material is to be stockpiled, increase required quantities by 10% to allow for waste» — WSDOT Design Manual. It is a road-building manual, but the arithmetic of waste does not change in a garden.

Where this stops being exact

• The default depth is an assumption. The form starts at 1 inch, roughly a bedding course, and it is our choice rather than a published recommendation. A play area or a base layer is several times deeper.
• The weight is a band, and half of it is ours. Only the compacted figure has a source. Anything quoted for loose sand here is an estimate we have labelled as such.
• WSDOT is a highway manual. Its subject is base, surfacing and ballast for road construction. Sand is sand, but a bagged play sand and a screened concrete sand are not the same material, and neither is quite what the manual is describing.
• Compaction eats depth. A bed screeded to your target depth ends up shallower once it is tamped or driven on. The 10% allowance is for waste, not for compaction — plan for both.
• Area first. If you have measurements rather than an area, the square footage calculator turns width and length into the number this page wants.