Sand Calculator

A hundred square feet, two inches deep

The case the form hint quotes is the one every sand estimate reduces to. A 10 × 10 ft sandbox base is 100 sq ft. Two inches is 2 ÷ 12 = 0.1667 ft, and 100 × 0.1667 = 16.67 cu ft of sand — 0.617 cu yd once divided by the 27 cubic feet in a yard. The 5% cushion for screeding overrun and settling takes that to 0.648 cu yd; a yard that sells whole yards supplies 1, and 0.35 cu yd of it is spare. Written as one line: cu yd = area sq ft × (depth in ÷ 12) ÷ 27. Both divisors are definitions, so the only figure in that line anyone can argue with is the cushion, and the form hands that one to you. No number on this page was typed in by hand: each was produced by the sand engine when the page was built, from the inputs the sentence around it describes.

If cubic feet and cubic yards are not yet second nature — why a yard is 27 cubic feet, what a cubic meter is in either, how an area and a thickness turn into a volume — start with the guide Cubic feet, cubic yards, and ordering concrete. Its examples are slabs, but a slab and a bedding layer are the same shape to the arithmetic. This page takes the units as read and concentrates on what is particular to sand: a thin layer, a whole-yard order, a weight that is never assumed, and a bag count the tool declines to make.

From footprint to order, one stage at a time

The sand engine is a clone of the topsoil engine and runs the five stages the methodology page documents for every estimator — geometry, coverage, waste, package rounding, user-priced cost. Two of those stages reduce to a definition here, because sand bought in bulk has no package to count and no published yield to divide by.

1. Geometry — the footprint and the layer. The engine wants a footprint in square feet and a depth in inches. It takes the footprint from length × width when the area field is empty, and from the area field alone when that field holds a number; the two routes cannot be combined, and the engine refuses an input that supplies both. Depth ÷ 12 is the layer's thickness in feet, and footprint × thickness is the net volume in cubic feet. That single unrounded figure is carried forward and also expressed in cubic yards (÷ 27); for the metric readout the page converts it to cubic meters with 0.028316846592, the international foot cubed. Metric entries are turned into feet, inches, and square feet before any of this happens, so a metric load and an imperial one take an identical path through the engine. A depth of zero is refused: a layer with no thickness has nothing to order.
2. Coverage — a definition, not a yield. Where the paint tool divides by square feet per gallon and the concrete tool by cubic feet per bag, the sand tool divides by 27, because the thing you buy is the cubic yard itself. No manufacturer figure enters the chain, and that is also why the chain carries no weight: a cubic yard of damp masonry sand and a cubic yard of dry concrete sand are the same volume and different loads on the scale, so the materials data holds no sand density at all. Density is yours to type from the supplier's quote, or to leave blank.
3. Waste — the cushion. The cubic-feet volume is multiplied by (1 + cushion ÷ 100) before anything is rounded. The form's default of 5% comes from the site's materials data, where it is recorded as a trade convention for bulk aggregate and mulch — depth variation being the main overrun — rather than as a measured or manufacturer figure; any percentage from zero to a hundred can replace it. The cushioned volume, in cubic yards, is the adjusted line on the result: the sand the layer is expected to consume once screeded and settled.
4. Package rounding — whole yards. One cubic yard is the "package", so the order is the adjusted volume rounded up to the next whole yard: 0.648 becomes 1 for the reference base. Nothing else in the chain rounds, and this stage only ever rounds up. The gap between the order and the adjusted volume is reported as spare — sand the whole-yard rule makes you buy on top of the cushion. An adjusted volume that lands on a whole number, within one part in a billion, is treated as the exact fit it is, so binary floating-point noise never buys a phantom yard.
5. User-priced cost — only if you price it. A price per cubic yard, if you type one, is multiplied by the order — the whole yards you pay for, not the adjusted volume. The site keeps no sand price and offers none; an empty price field means no cost line.

Tons are computed beside the pipeline rather than in it. With a density in the field, the engine multiplies the adjusted cubic yards — stage three's figure — by it, and the panel reports the product as the weight of sand the job is expected to use at your supplier's number. The engine checks only that the density is above zero and no higher than 10 tons per cubic yard, a ceiling shared with the gravel engine to catch a typo; it says nothing about what any sand weighs.

What each field moves

Length and width are the footprint's two sides in decimal feet, and their product is the only thing the engine takes from them. Doubling either doubles the net and adjusted volume; the order then follows in whole-yard steps, so it may double, or jump by more or less than that, depending on where the adjusted figure sat relative to a yard boundary. There is no inches box beside these fields: a tape reading of 12 ft 6 in goes in as 12.5, the inches divided by 12 and added to the feet, which is how every dimension on the site is normalised before arithmetic. The feet & inches calculator does that division for readings with awkward fractions.

The area field is for a footprint that is not one rectangle — a border that wraps a patio on three sides, a sandbox with a notch for a bench, a run of bedding under a curved walk. Break it into pieces, total them on the square footage calculator, and paste the sum here; in metric mode the field takes square meters. The form gives this field priority: while it holds a number, length and width are not read at all. That is convenient when a total arrives from elsewhere and a trap when a total from the last estimate is still sitting there.

Depth is where sand estimates go wrong. It is small next to the other two dimensions, it is the one field entered in inches rather than feet, and its value comes from outside the calculator — the paver manufacturer's bedding figure, the sandbox plan, the job drawings. The tool makes no judgment about it: enter 1 in and it sizes a one-inch layer, enter 24 and it sizes a two-foot one. Because the volume is proportional to the depth, every error in this field passes straight through to the order, which is what makes the inches-versus-feet slip below so expensive.

The cushion scales the volume, so the adjusted line moves smoothly with it while the order moves only when the adjusted figure crosses a yard boundary. A change of a point or two often leaves the order untouched; then one more point tips it by a full yard. On a thin bedding layer the round-up usually outweighs the cushion altogether, and the examples below put the two figures side by side so you can see which one decided the order.

Supplier density and price change no volume. Density produces the tons line and nothing else; price produces the cost line and nothing else. Both can be filled in later — when the quote comes back by the ton, or when the price is known — without disturbing the figures above them. Density is entered in US tons per cubic yard, and the ceiling of 10 is there to refuse a pounds figure typed by mistake.

Units is a presentation switch. Metric mode relabels the fields to meters, centimeters, and square meters, converts each entry with the exact definitions of the foot (0.3048 m), the inch (2.54 cm), and the square foot (0.09290304 m²) before the engine runs, and leads the result with cubic meters. The whole-yard order still appears beneath, because that is the unit the sand is sold in.

What this page holds, and what it leaves to you

• Cushion default, 5%. Status: trade convention, as the site's materials data labels it; the entry there notes that no primary source publishes a universal figure and that for bulk aggregate and mulch depth variation is the main overrun the allowance covers. Adjustable in the form, down to zero.
• Ordering increment, 1 cu yd. The sand engine rounds to whole yards because, as the FAQ notes, bulk sand is sold by the yard; this is a convention of the trade, not a figure from the materials data, and a yard that sells half-yard scoops changes only the last stage. The adjusted volume is printed beside the order for exactly that case.
• 12 inches to the foot; 27 cubic feet to the cubic yard. Definitions.
• 0.3048 m to the foot; 2.54 cm to the inch; 0.09290304 m² to the square foot; 0.028316846592 m³ to the cubic foot. Exact definitions following from the international foot. The first three convert metric entries inward; the last two present the footprint and the volumes outward.
• Density ceiling, 10 tons per cubic yard. A validation limit the sand engine borrows from the gravel engine. It is a tripwire for a unit mistake, not a property of sand.
• Sand density — none. Bag coverage — none. The materials data holds neither, deliberately: what a yard weighs depends on the product and its moisture, and the volume in a weight-labelled bag depends on the same two things. The first comes from your supplier's quote and the second from the bag, as the FAQ explains.

10 loads through the engine

The table holds 10 runs of the sand engine made when this page was built, with the inputs in the first column and the engine's own output in the rest. They were picked to exercise different corners of the chain rather than to look like typical jobs: a base with and without its cushion, a bedding layer thin enough that the round-up is most of the order, a total that came in through the area field, a volume that lands exactly on three yards, a side measured in feet and inches, two loads that go on to a tons line and a cost line below, and one entered in meters and centimeters. The cushion is 5% except where the first column says "no cushion". The depths are inputs chosen for the arithmetic, not recommendations for any job.

Reference base, cushion on and off. At 5% the 100 sq ft base's 0.617 cu yd becomes 0.648 cu yd adjusted, which a whole-yard supplier fills with 1 cu yd, leaving 0.352 cu yd spare. Take the cushion to 0 and the adjusted volume drops back to the net 0.617, yet the order is still 1 cu yd with 0.383 spare: removing the allowance removed nothing from what you buy, because the round-up, not the cushion, was setting the order. At this scale a half-yard scoop or a few bags, counted from the adjusted or the net line, may fit the job better than a full yard.

Bedding under a patio. 12 × 16 ft of pavers over a sand bed entered at 1 in — the figure comes from the paver maker's instructions, not from here — covers 192 sq ft but holds only 16 cu ft, 0.593 cu yd. Cushioned, that is 0.622 cu yd; ordered, it is 1 cu yd, and 0.378 cu yd of that single yard is spare. The footprint is nearly double the reference base's and the volume a little under it: in a thin layer the round-up is at its coarsest relative to the need, and the spare — not the cushion — is the figure to look at when deciding whether a scoop will do.

An irregular bed, totalled elsewhere. Say a border was measured in pieces and summed on the square footage calculator to 150 sq ft. Pasted into the area field with a depth of 3 in (0.25 ft), it is 37.5 cu ft, 1.389 cu yd net, 1.458 cu yd cushioned, and an order of 2 cu yd with 0.542 cu yd spare. The engine sees a number of square feet and a depth; whether those square feet were a rectangle, an L, or a crescent never reaches it.

Three yards exactly. 27 × 9 ft is 243 sq ft, and at 4 in (0.3333 ft) that is 81 cu ft — 3 cu yd on the nose. With no cushion the adjusted figure is a whole number of yards, the order is 3 cu yd, and the spare is 0. Here the product happens to be exact in binary floating point, so the plain round-up already lands on 3; on an input where the arithmetic leaves the figure a hair over the boundary, the engine's exact-fit tolerance of one part in a billion is what keeps a phantom yard from appearing — the methodology page shows that case with the guard acting. Put the default 5% back and the adjusted volume is 3.15 cu yd, the order 4, the spare 0.85 cu yd — a cushion worth a fraction of a yard has bought a whole one. This is the row to remember when a small allowance seems harmless: read the adjusted line and the spare together before accepting the order.

Twelve feet six. One side of the bed measures 12 ft 6 in and the other 10 ft; the first goes in as 12.5. At 3 in the 125 sq ft footprint holds 31.25 cu ft (1.157 cu yd), cushioned to 1.215 cu yd and ordered as 2 cu yd with 0.785 cu yd spare. The misreadings section shows what typing the same reading as 12.6 would have done.

A load the supplier sells by weight. 30 × 40 ft at 4 in is 1,200 sq ft and 400 cu ft: 14.815 cu yd net, 15.556 cu yd with the cushion, 16 cu yd to order, 0.444 cu yd spare. On a load this size the round-up is a sliver of the order and the cushion is what sets it. Now suppose the density field holds a stand-in of exactly 1 ton per cubic yard — chosen so the multiplication is visible, not because any sand weighs that; the site holds no sand density. The tons line reads 15.56: the same number as the adjusted line, in tons, because tons are adjusted cubic yards × density. Had the engine weighed the order instead, the line would read 16. The only density that belongs in the field is the one on your supplier's quote, and the tons line is then the figure to give a supplier who sells by the ton.

A priced load. 20 × 10 ft at 3 in is 50 cu ft, 1.852 cu yd net; with the 5% cushion, 1.944 cu yd; ordered, 2 cu yd with just 0.056 cu yd spare, because the adjusted volume stopped a hair under the boundary. Type $50.00 per cubic yard — a placeholder for the arithmetic, since the site holds no sand prices — and the cost line reads $100.00: 2 ordered yards at that price. It is the order that is priced, not the adjusted volume, because the yard bills you for whole yards.

Metric in, metric out. With the toggle on Metric, 4 × 2.5 m at 5 cm is converted to 13.12 × 8.2 ft at 1.97 in before the engine runs. The engine returns 107.64 sq ft and 17.66 cu ft (0.654 cu yd); the panel shows those as 10 m² and 0.5 m³. Cushioned at 5% the layer is 0.525 m³, and the order is still a whole US yard — 1 cu yd, or 0.765 m³ — because the rounding unit does not change with the display. The headline reads in cubic meters; the figure to phone through to a yard that sells by the cubic yard is the one beneath it.

Why the tons line waits for your supplier

Sand's volume math is exact; its weight is not, because "sand" is a family of products. Washed concrete sand, fine masonry sand, and damp fill dirt-sand blends each land somewhere different on the scale, and moisture alone can add hundreds of pounds to the identical yard. A built-in density would have to pick one product at one moisture and present the result as if it applied to the sand on your truck, so the materials data holds none and the engine has nowhere to look one up. Type the figure from your supplier's quote sheet and the conversion is theirs; leave the field blank and the result stops at cubic yards, complete. The same rule governs money: the only cost shown is computed from the price you entered.

The field takes US tons per cubic yard. A quote written in pounds per cubic yard has to be divided by the pounds in a US short ton before it goes in — the construction unit converter does that — and the ceiling of 10 tons per cubic yard exists to refuse one that was not, rather than print a weight that is nonsense.

Which line answers which question

The result panel prints four lines for every load and up to two more, and a sand order usually turns on a different one depending on who is selling. The top line, Order N cu yd, is the whole-yard figure: give it to a yard or a delivery service that sells by the yard. Net … sq ft footprint restates the footprint the engine used and the raw volume in cubic feet and cubic yards; it is the line to check first, because a wrong footprint or a stale area field shows up here before the cushion and the rounding dress it. The cubic feet on this line are also the figure to divide by a bag's printed volume if the sand is coming home in bags. With N% extra is the cushioned volume and the figure to quote to a yard that sells by the half-yard scoop, since it carries the allowance without the whole-yard round-up. Rounded to whole yards repeats the order with the spare in brackets, so the cost of the round-up is visible as a number rather than buried. A fifth line, At your supplier's density, appears only once a density is typed and gives the tons the adjusted volume weighs at that figure — the line for a supplier who sells by the ton. A sixth, Estimated sand cost, appears only once a price is typed and prices the order. In metric mode the top three lines read in cubic meters and the whole-yard line is relabelled as US yards; the figures underneath are the same. Copy result puts a short plain-text summary of the result on the clipboard, and Reset clears every field, the area field included, and returns the toggle to Imperial.

Slips the panel can and cannot catch

Two feet of sand. The depth field takes inches; the sides take feet. Type the reference base's 2 in as if the field took feet and the engine receives 24 in. The footprint is unchanged at 100 sq ft, but the layer is now 200 cu ft and 7.407 cu yd net, and the order is 8 cu yd where 1 was right — 12 times the volume, the ratio of inches to the foot. The engine cannot object, because a two-foot layer is a legitimate input; the sandbox has become a sand pile. A cubic-yard figure that looks absurd for a thin layer is the signal, and the depth field is the first place to look. The guide linked above shows the mirror slip, feet typed where inches were wanted, which under-buys by the same factor.

Meters typed as feet. The metric load is 4 × 2.5 m at 5 cm. Leave the toggle on Imperial and type the same three numbers, and the engine is handed a 4 × 2.5 ft footprint 5 in deep: 4.17 cu ft where the real layer is 17.66. Here both versions round up to 1 cu yd, and that is the lesson — the whole-yard order can swallow a slip that the net line shows plainly. If the cubic feet look too small for the footprint you measured, check the toggle before anything else.

Point-oh-five. The cushion is a percentage, so the default is typed as 5, not as the decimal fraction 0.05. Enter the latter on the weighed load and the engine applies 0.05%: the adjusted volume falls from 15.556 to 14.822 cu yd and the order from 16 to 15 cu yd. A twentieth of a percent is a valid cushion, so nothing is flagged; the only tell is the percentage printed on the With … extra line.

Feet-point-inches. 12 ft 6 in is 12.5 ft; typed as 12.6 it is 0.1 ft too long. On the twelve-six load the difference is 31.5 cu ft against 31.25, and the order is 2 cu yd either way, but the slip grows with the inches: 12 ft 11 in typed as 12.11 is 0.81 ft short of the 12.917 ft the tape read.

Last week's area. A number left in the area field from an earlier estimate is still the footprint, whatever the length and width now say. Two different beds will produce the same order until the field is cleared or Reset is pressed; the net line, which names the footprint used, is where the mismatch shows.

Ordering the tons. Tons weigh the adjusted volume; the order counts whole yards. On the weighed load those are 15.556 and 16 cu yd, and the spare is the difference. Give a by-the-ton supplier the tons line and a by-the-yard supplier the order line; do not translate between them with a density you did not get from the supplier in question.

Padding the padding. Rounding 12.5 up to 13 before typing it, keeping the cushion, and then asking the yard for one more "to be safe" stacks three allowances where the chain already carries two: the cushion on the volume and the round-up on the cushioned volume, applied once each in that order. The reference base with its cushion at zero shows what the round-up alone contributes. If your layers habitually come out thicker than planned, that is depth variation, the overrun the cushion exists to cover: raise the cushion rather than inflating a side.

What is outside the model

The engine computes one layer of uniform thickness over one footprint and cushions it by one flat percentage. A bed that is deeper at one end, a base that is not flat, a grade that slopes, edges that feather out — none of these is modelled; they are the reasons the sand placed differs from the sand calculated, and the cushion is the single number you have for all of them. Compaction is outside the model: the volume computed is the layer as dimensioned. If your product's instructions call for compaction, any allowance for it is yours to add through the cushion field; the default covers depth variation only. Nothing about weight is modelled until you supply a density, nothing about bags at all, and nothing about the supplier — minimum loads, scoop sizes, how a load is measured at the yard. Which sand to buy and how deep to lay it are questions for the product's instructions and the project's drawings; the tool sizes the layer you describe and, as the note beneath the form says, leaves bedding specifications, compaction, drainage, and anything structural to a qualified contractor or engineer. Whole-yard rounding is the trade's convention rather than a rule, and a yard that sells smaller scoops changes only the last stage. The remaining simplifications are those the methodology page lists for every estimator.

Related tools and guides

Two other estimators run sand's chain on a different material: the gravel calculator for base rock under slabs and pavers, and the topsoil calculator for planting beds and grading. If this sand is going under pavers, the paver calculator figures the bedding layer and the paver count together. Before you come here, the square footage calculator settles an irregular footprint for the area field and the feet & inches calculator turns tape readings into decimal feet; afterwards, the construction unit converter moves the result between cubic yards and cubic meters or a quote between pounds and tons. The guides behind the chain are cubic feet, cubic yards, and ordering concrete for the units, waste factors, explained for the one input that is a judgment, and metric and imperial in the estimators for the toggle; the rest are at all guides.

Frequently asked questions

Nothing you type leaves your device. See how estimates are constructed and tested on the methodology page.