Article — Sand Calculator
Sand calculator: cubic yards, tons, and bags for any project
A sand calculator converts length, width, and depth into the cubic yards or cubic metres of sand needed to fill the area, plus the weight in tons and the number of bags. The core formula is volume = length × width × depth, with unit conversion applied. Dry all-purpose sand weighs about 100 lb/ft³ (1,600 kg/m³). A 12 × 14 ft patio at 2 inches deep needs 1.04 cubic yards or 1.4 short tons of sand. In bags, that is roughly 56 bags of 50 lb or 50 bags of 25 kg.
Sand comes in several grades — all-purpose, mason, play, and paver — each with its own density and use. Picking the right grade matters as much as the volume, because the wrong sand under pavers washes out within a season, and the wrong sand in a child’s sandbox can carry crystalline silica dust that should not be there.
The sand volume formula
In US units, cubic yards = (length in ft × width in ft × depth in inches) ÷ 324. The 324 is 27 cubic feet per cubic yard multiplied by 12 inches per foot. Depth in inches and length in feet is the common mix because sand layers are usually thin and shallow.
yd³ = (L_ft × W_ft × D_in) / 324 US unitsm³ = L_m × W_m × D_m metrictons = yd³ × 1.35 dry sand50 lb bags = tons × 40 US retail25 kg bags = metric tons × 40 EU retailThe metric version is cleaner. Cubic metres = length × width × depth, all in metres. A 4 m × 5 m patio at 0.05 m (5 cm) deep is exactly 1 m³, or 1.6 metric tons of dry sand. Bag counts match almost one to one: 1 metric ton fits in 40 bags of 25 kg, and 1 short ton fits in 40 bags of 50 lb.
Sand types and densities
Density varies about 15% across commercial sand grades. The differences look small until you multiply by hundreds of cubic feet, where one type can be 200 lb heavier per cubic yard than another.
- All-purpose sand = 100 lb/ft³ (1,600 kg/m³), coarse, used for concrete and general fill
- Mason sand = 105 lb/ft³ (1,680 kg/m³), fine, used in mortar joints
- Play sand = 98 lb/ft³ (1,570 kg/m³), fine and rounded, certified silica-free
- Paver sand = 103 lb/ft³ (1,650 kg/m³), coarse and angular, locks pavers in place
- Compacted sand = 110 lb/ft³ (1,760 kg/m³), machine-densified subbase
Wet sand weighs 10 to 15% more than dry because the water adds mass without changing the grain volume. Suppliers quote the dry weight; the actual delivered weight after a rainy week can be noticeably higher. For ordering purposes the dry figure is what counts.
Sand for paver bases
Paver installations need two layers under the pavers: 4 to 6 inches of compacted crushed-stone base, then 1 inch of bedding sand. The bedding sand must be coarse (paver-grade), not fine (mason or play). Fine sand washes out under foot traffic within a season, and the pavers settle unevenly.
A 200 ft² patio at 1 inch bedding sand needs (200 × 1) ÷ 324 = 0.62 cubic yards, or about 0.85 short tons. Polymeric sand fills the joints from above once the pavers are set; that material is a separate purchase, typically 1 bag of poly sand per 50 ft² of paver surface.
Sand for sandboxes and play areas
Sandbox sand must be certified play sand, meaning it has been washed and screened to remove silica dust and organic debris. The certification matters because crystalline silica is a known respiratory irritant when airborne, and small children kick up dust constantly. Commercial play sand carries a label or specification sheet listing the silica content.
A 6 ft × 6 ft sandbox at 6 inch depth needs (6 × 6 × 6) ÷ 324 = 0.67 cubic yards = 1,800 lb = 36 bags of 50 lb play sand. Order delivered if you can — moving 36 bags from a car to a sandbox is more work than the install itself. Replace the sand once a year because rain and debris degrade it over time.
Sand for concrete and mortar mixes
Standard concrete uses a 1: 2: 3 ratio by volume — one part cement, two parts sand, three parts gravel. For every cubic yard of concrete, you need about 0.5 yd³ of sand. Mortar mix is different: a 1: 3 ratio of cement to mason sand, so a cubic yard of mortar mix needs 0.75 yd³ of sand. Mason sand only — concrete sand is too coarse for mortar joints.
The US Geological Survey reports that construction sand and gravel together form the second-largest non-fuel mineral commodity by volume in the US, after crushed stone. Annual production exceeds 900 million metric tons, valued at over $11 billion. Most of it travels less than 50 miles from quarry to job site because hauling sand long distances is uneconomical at current prices.
Bulk sand vs bagged sand
Bulk sand delivered by the truck costs $20 to $60 per ton plus delivery. The breakeven point against bagged sand is around 2 to 3 cubic yards. Below that, bagged sand from a hardware store is more convenient and cheaper after counting transport time. Above 3 yd³, bulk delivery is much cheaper per ton.
Bulk suppliers stock multiple grades and ship whatever is queued unless you specify. Ordering "sand" without grade can produce mason sand for a paver base or paver sand for a sandbox. Both are wrong. Always confirm the grade in writing on the delivery ticket before the truck dumps.
Common sand calculation mistakes
The most frequent error is unit confusion. Depth in inches with length and width in feet is the standard mix, so dividing by 324 (not 27) gives cubic yards. Dividing by 27 produces an answer 12 times too large; dividing by 12 produces one 27 times too small.
The second mistake is forgetting compaction. Loose sand loses 15 to 25% of its volume under load. A paver base needs the upper end of that allowance because vehicle wheels and foot traffic densify the sand continuously. Order the calculated volume times 1.15 to 1.25 if the install will see real load.
Sand storage and longevity
Sand keeps indefinitely under cover. Outdoors, rain washes fine grains downward and contaminates the rest with soil and organic matter. Tarps or sand bins solve both problems. For sandboxes, an evening cover keeps cats out and reduces the year-end refresh from full replacement to a top-up.
Bagged sand stored in a garage stays usable for years if the bags remain intact. Punctured bags absorb moisture and clump within a season. Store flat on a pallet to keep moisture from rising up from a concrete floor, and rotate stock so the oldest bags come out first.