The cubic yard calculator above converts an area and a spread depth into a volume, and reports it four ways: cubic yards, cubic metres, cubic feet, and the number of truck loads it represents. It handles rectangles, circles and triangles, multiplies up for repeated areas, applies a waste allowance, and rounds the answer up to a quantity a supplier will actually sell you.
Arb Digital builds free calculators for the arithmetic between a plan and a delivery, and bulk material is where that arithmetic goes wrong most often. The trap is not the multiplication — it is the units. Depth is specified in inches, the area is in feet, and the material is sold in yards, so a single division by 27 sits between a correct answer and a driveway with twice the gravel it needed.
What This Cubic Yard Calculator Does
A cubic yard is the volume of a cube three feet on each side, which is 27 cubic feet or about 0.7646 cubic metres. It is the standard unit for selling bulk material in the United States and Canada — gravel, topsoil, sand, mulch, crushed stone, fill — and it is the number a supplier will ask for when you phone in an order.
The tool takes an area and a depth, produces the volume, and then does three things that matter more than the multiplication. It converts between the units the measurement was taken in and the units the material is sold in. It applies a waste and compaction allowance, because loose material settles and spreading is never perfectly even. And it rounds the result up to a purchasable quantity, since bulk yards deal in whole or half units rather than the 3.259 cubic yards your geometry actually calls for.
One boundary is worth stating plainly, because the two tools sit close together. Our concrete calculator is specific to concrete: it handles slabs, footings and columns, and it converts the volume into pre-mixed bag counts. This page is the generic bulk-material volume tool, for anything that arrives loose in a truck and gets spread rather than poured and cured.
How to Use It
- Set the units. Imperial takes feet for the area and inches for the depth. Metric takes metres and centimetres. Both report all four volume figures, so you can order in either system.
- Pick the shape and enter the dimensions. For anything irregular, split the site into rectangles, circles and triangles, run each one, and add the results. That is far more accurate than averaging a curved edge by eye.
- Enter the spread depth. This is the single most consequential input, because volume scales directly with it. Two inches versus four inches is exactly double the material and double the bill.
- Set the waste and compaction factor. Ten per cent is a sensible default for loose material spread on a prepared surface. Raise it well above that for anything that will be compacted.
- Read the order quantity, not the raw volume. The hero figure includes waste and is rounded up to whatever increment your supplier sells. The grid keeps the raw number visible so you can see the difference.
The Formula / How It's Calculated
The volume is area × depth, with everything converted into consistent units first. In imperial that means cubic yards = (length × width × depth ÷ 12) ÷ 27, where length and width are in feet and depth is in inches. The division by 12 turns inches into feet; the division by 27 turns cubic feet into cubic yards.
Work the default example. An area 20 feet by 12 feet is 240 square feet. A 4-inch depth is 4 ÷ 12 = 0.3333 feet. The volume is 240 × 0.3333 = 80 cubic feet, and 80 ÷ 27 = 2.963 cubic yards. Add a 10% waste allowance and you get 3.259 cubic yards. Rounded up to whole units, the order is 4 cubic yards, which fits comfortably in one 10-yard truck.
The metric conversions follow from the exact definitions rather than from approximations. The inch is exactly 25.4 millimetres by international agreement, as NIST's reference on SI units of length records — a 1959 standardisation among English-speaking nations. From that, a yard is exactly 0.9144 metres, so a cubic yard is 0.9144³ = 0.764554857984 cubic metres exactly. Our 2.963 cubic yards is therefore 2.265 cubic metres, or 2.492 once waste is added. NIST also publishes broader unit conversion guidance covering length, area, volume and mass in both systems.
The Division by 27 Is Where Orders Go Wrong
Three feet is a yard, so many people assume three cubic feet is a cubic yard. It is not — a cubic yard is 3 × 3 × 3 = 27 cubic feet. That single misunderstanding produces an order nine times too large, and because bulk material is cheap per unit and expensive to move, the mistake shows up as a mountain on the driveway rather than a rounding error on the invoice.
The inverse error is just as common and more expensive in time. Someone calculates 80 cubic feet, orders 80 units, and is told the price is for cubic yards. Ordering 80 cubic yards of gravel when you needed 3 means roughly eight truck deliveries, all of which have to be paid for and most of which have to be removed again.
The safest habit is to keep the units attached to every number as you work, and to sanity-check the result against something physical. A cubic yard covers about 100 square feet at three inches deep, or about 160 square feet at two inches. If your answer implies covering a whole garden with one yard, or forty yards for a single flower bed, the arithmetic has gone wrong somewhere. The volume converter handles the conversions on their own if you just need to move a figure between systems.
Choosing the Right Depth
Depth is where the money is, and it is usually specified by function rather than preference. Decorative gravel over a weed membrane is typically spread thin, because it only has to hide the surface. A gravel driveway that carries vehicles is a structural layer, and it needs enough depth to distribute the load without rutting — often several times the decorative depth, sometimes in two layers of different stone sizes.
Mulch has its own logic: too thin and weeds come through and moisture escapes; too thick and it can hold water against stems and starve roots of oxygen. Topsoil depth depends on what is being grown, since turf needs far less root depth than a vegetable bed. In every case, the right number comes from the specification for the job, and this calculator is agnostic about it — get the depth from your landscape designer, groundworks specification or supplier's guidance, then bring it here.
One geometric point that catches people out: volume scales linearly with depth but the surface area does not change, so a depth increase feels invisible and costs proportionally. Going from three inches to four is a 33% increase in material for a change nobody will see. If the budget is tight, reducing depth by a fraction of an inch across a large area saves more than trimming the edges of the area itself. For the material-specific rules, our mulch calculator and gravel calculator go into the depths each one needs.
Waste, Compaction and Why Loose Volume Is Not Placed Volume
The waste factor on this page does two different jobs, and it is worth separating them. The first is ordinary waste: material lost in transfer, spread slightly deeper than intended in places, left in the barrow, or spilled. On a straightforward job that is a few per cent.
The second is compaction, and it can be much larger. Material delivered loose occupies more volume than the same material once it has been compacted in place. A base layer under a patio or driveway that is mechanically compacted will settle noticeably, and you need to order the loose volume that produces your target compacted depth — not the compacted volume itself. The size of that allowance depends on the material and the degree of compaction specified, so take it from your groundworks specification rather than assuming.
Bulk material is also sold by volume but hauled by weight, and trucks have weight limits as well as volume limits. A 10-yard truck may not be able to carry 10 yards of wet sand within its legal axle load, and suppliers will split the delivery accordingly. If tonnage matters for access, a lift, or a charge, work it out with the material weight calculator before you book.
Measuring an Irregular Area
Real sites are rarely rectangles. The reliable method is decomposition: overlay the shape with rectangles, triangles and circle segments, measure each, and add them. It takes longer than pacing the perimeter and guessing, and it is dramatically more accurate.
For a long curved bed, treat it as a series of trapezoids: measure the width at regular intervals along its length, average adjacent pairs, and multiply by the interval. For a circle, measure the diameter across the widest point rather than trying to measure the radius from a centre you cannot locate on the ground. For a ring — a border around a patio — calculate the outer circle and subtract the inner one rather than trying to measure the ring directly.
Whatever method you use, measure twice and write the numbers down. A 5% error in a length measurement becomes a 5% error in the volume, which on a large job is a meaningful sum. Our square footage calculator handles the area side of this for complex shapes, and the rectangle area calculator is the quickest route for the simple case.
Arb Digital builds free, no-signup calculators for construction, energy, statistics and finance. Browse the full library, or get in touch if there is a calculation your team keeps doing by hand.
Browse All Free Tools Contact Arb DigitalCommon Mistakes to Avoid
- Dividing cubic feet by 3 instead of 27 — a cubic yard is three feet in every direction, so it holds 27 cubic feet, not three.
- Leaving the depth in inches — multiplying feet by feet by inches gives a number in no unit at all. Convert the depth first.
- Ordering the compacted volume for a compacted layer — you buy loose material, and it occupies more space in the truck than it will once it is rolled.
- Measuring a curved bed as one rectangle — split irregular areas into simple shapes and add them, rather than averaging by eye.
- Assuming a truck can carry its rated volume — weight limits bite before volume limits on dense or wet material, so check the tonnage too.
Related Free Tools From Arb Digital
Work out poured concrete and bag counts with the concrete calculator, get depth guidance for garden material with the mulch calculator and the gravel calculator, convert between volume units on their own with the volume converter, measure a complex plan with the square footage calculator, and check delivery tonnage with the material weight calculator. The full free online tools hub holds the rest of the construction set.
Frequently Asked Questions
Twenty-seven. A cubic yard is a cube three feet on each side, so it is 3 × 3 × 3 cubic feet. Dividing by 3 instead of 27 is the single most common error in bulk material ordering.
Multiply the length and width in feet, multiply by the depth in inches divided by 12, then divide the result by 27. For 20 by 12 feet at 4 inches deep, that is 240 × 0.3333 = 80 cubic feet, which is 2.963 cubic yards.
Exactly 0.764554857984 cubic metres, usually rounded to 0.765. This follows from the yard being defined as exactly 0.9144 metres, which in turn comes from the inch being exactly 25.4 millimetres.
Ten per cent is a sensible default for loose material spread on a prepared surface. Increase it substantially for any layer that will be mechanically compacted, since loose delivered volume is greater than the placed volume once rolled.
It depends entirely on depth. One cubic yard is 27 cubic feet, so at three inches deep it covers about 108 square feet, and at two inches about 162 square feet. Divide 27 by the depth in feet to get the coverage.
The raw figure is the pure geometry. The order figure adds your waste allowance and rounds up to the increment your supplier sells in, because bulk yards deal in whole or half units rather than three decimal places.
You can get the volume, but the concrete calculator is the better tool for that job. It handles slab, footing and column geometry directly and converts the volume into pre-mixed bag counts, which this generic tool does not.
Break it into rectangles, triangles and circles, calculate each separately, and add the results. For a long curved bed, measure the width at regular intervals and treat it as a series of trapezoids rather than estimating an average width.
This calculator is provided for education and planning only. Quantities are estimates and exclude delivery, compaction specification and site conditions. Confirm depths and material specifications with your supplier or groundworks contractor before ordering.
