A cubic yard is a cube 3 feet (0.91 m) on each side, and nearly every bulk landscape material, from shredded bark to ready-mix concrete, is sold by it. The calculator multiplies your area by your depth, converts the result to cubic yards, and turns that into bags and an approximate weight.
The volume is the same whatever fills it. What changes from one material to the next is the depth the job needs, how much extra to buy and how heavy the load is, and those three decisions are where most ordering mistakes start.
How to use the cubic yard calculator
Pick the job, measure the area in feet, set the finished depth, and the calculator returns cubic yards with your chosen extra already added.
- Choose the job. Each of the six jobs, from Mulch a bed to Pour a concrete slab, loads a starting depth and material. A one-line note under the menu gives the recommended range for that job. Something else clears the material to Volume only.
- Measure each area. Enter a rectangle as length and width, a circle as its diameter measured straight through the center, and a triangle as its three sides, which are easier to tape in a yard than a perpendicular height. Known area takes square footage straight from a plan or survey. In feet mode, lengths go in as decimal feet, so divide any odd inches by 12: 7 inches (18 cm) is 0.58 of a foot.
- Split odd shapes. An L-shaped border is two rectangles; a bed with a rounded end is a rectangle plus a circle. Add another area for each piece and the calculator adds them together. Switch to meters and centimeters if your tape reads metric, and the numbers you have typed convert with it.
- Set the depth. Use the finished depth: the thickness after soil has settled, or the inside height of the forms for concrete. Depth goes in as inches (centimeters in metric), never feet.
- Pick the material, bag size and extra. Material changes only the weight and the type of bag, never the volume. Choose the bag size printed on the bags you plan to buy, and an extra of none, 5, 10 or 15%; 10% is the default.
The result shows cubic yards in large type (cubic meters in metric mode), with the other units underneath. Below that come the number of whole bags, an approximate weight with its low-to-high range, and how many square feet one yard covers at your depth. Choose Volume only to see the bare volume before any extra.
How the cubic yard math works
Area in square feet times depth in feet gives cubic feet; divide by 27 and you have cubic yards. Only the area formula changes with the shape:
- Rectangle: length × width.
- Circle: 3.1416 × radius × radius, where the radius is half the diameter.
- Triangle: ½ × base × perpendicular height. From three sides a, b and c, find s, half the perimeter, and the area is the square root of s × (s − a) × (s − b) × (s − c). The calculator uses this second method.
- Volume: cubic feet = square feet × depth in inches ÷ 12, and cubic yards = cubic feet ÷ 27.
Here is the job the calculator opens with: a bed 20 by 10 feet (6.1 × 3.05 m) mulched 3 inches (7.6 cm) deep, with 10% extra and 2 cubic foot bags.
- Area. 20 × 10 = 200 square feet (18.6 m²).
- Volume. 200 × 3 ÷ 12 = 50 cubic feet (1.42 m³).
- Cubic yards. 50 ÷ 27 = 1.85 cubic yards.
- Extra. 50 × 1.10 = 55 cubic feet, and 55 ÷ 27 = 2.04 cubic yards (1.56 m³) to order.
- Bags. 55 ÷ 2 = 27.5, so buy 28 bags.
Now give that bed company. A round bed 10 feet (3.05 m) across is 3.1416 × 5 × 5 = 78.54 square feet, or 19.6 cubic feet at the same depth (0.727 cubic yard). A corner triangle with sides of 9, 12 and 15 feet (2.7, 3.7 and 4.6 m) has s = 18. Its area is the square root of 18 × 9 × 6 × 3, which is 54 square feet (5 m²). Mulch at the same depth fills 13.5 cubic feet: exactly half a yard. All three together come to 83.1 cubic feet, or 3.08 cubic yards before the extra and 3.39 with it.
What a cubic yard holds
Besides its 27 cubic feet, a cubic yard holds 46,656 cubic inches, 0.7646 cubic meter (764.6 liters) or about 202 US gallons. Dividing cubic feet by 3 instead of 27 is the classic slip, and it turns a two-yard order into eighteen.
The 324 shortcut for square feet and inches
Because depth is usually measured in inches, the two divisions can be rolled into one: 27 cubic feet per yard × 12 inches per foot = 324. Multiply square feet by depth in inches and divide by 324. For the opening bed, 200 × 3 ÷ 324 gives the same 1.85 cubic yards in a single step. In metric, square meters × depth in centimeters ÷ 100 gives cubic meters, and each cubic meter is 1.308 cubic yards.
How far a cubic yard goes at each depth
One cubic yard covers 324 square feet divided by the depth in inches, so every inch you add shrinks the area a yard can reach.
| Depth | One cubic yard covers |
|---|---|
| 1 in (2.5 cm) | 324 sq ft (30.1 m²) |
| 2 in (5.1 cm) | 162 sq ft (15.1 m²) |
| 3 in (7.6 cm) | 108 sq ft (10 m²) |
| 4 in (10.2 cm) | 81 sq ft (7.5 m²) |
| 6 in (15.2 cm) | 54 sq ft (5 m²) |
Any material: 27 cubic feet spread at each depth.
Turned around, each inch of depth over 1,000 square feet (93 m²) takes 3.09 cubic yards, which is handy for lawns and large beds measured off a survey. The same arithmetic works for a single bag: multiply its cubic feet by 12 and divide by the depth in inches. A 2 cubic foot bag spread 3 inches (7.6 cm) deep covers 8 square feet (0.74 m²).
Work coverage out from the volume printed on the bag rather than the coverage claim beside it. One 2.5 cubic foot bag of lawn topping soil promises about 250 square feet at half an inch (13 mm), but 2.5 cubic feet spread that thin covers 60 square feet (5.6 m²).
Bags per cubic yard, and when bulk is cheaper
Divide 27 by the bag's volume in cubic feet and round up. For concrete, divide by the volume the bag makes once it is mixed with water, not by its weight.
| Bag | Bags per cubic yard |
|---|---|
| 0.5 cu ft bag (soil, compost, mulch) | 54 |
| 0.75 cu ft bag (soil, compost, mulch) | 36 |
| 1 cu ft bag (soil, compost, mulch) | 27 |
| 1.5 cu ft bag (soil, compost, mulch) | 18 |
| 2 cu ft bag (soil, compost, mulch) | 14 |
| 3 cu ft bag (soil, compost, mulch) | 9 |
| Concrete mix, 40 lb bag (0.30 cu ft) | 90 |
| Concrete mix, 50 lb bag (0.375 cu ft) | 72 |
| Concrete mix, 60 lb bag (0.45 cu ft) | 60 |
| Concrete mix, 80 lb bag (0.60 cu ft) | 45 |
Rounded up to whole bags. Concrete yields are for the mixed volume each bag makes.
Most soil, compost and mulch bags are labeled by volume, so the count is plain division. Concrete mix is labeled by weight, and its yield is printed on the bag. The yields in the table are for standard concrete mix; lightweight high-yield mixes make a different volume per bag, so check the bag before you count.
Bulk is not always the cheaper way to buy. National cost surveys (2025–2026) put bulk mulch at $25 to $135 a cubic yard before a delivery fee of $50 to $150, and bagged mulch at $2 to $13 a bag. Under about a yard, buy bags, since landscape suppliers sell bulk by the yard. On bigger jobs bulk tends to win once the fee is spread over several yards, but cheap bags can beat it on a one- or two-yard job. To compare your own quotes, multiply a bag's price by 27 and divide by its cubic feet. A 2 cubic foot bag costs 13.5 times its shelf price per yard, so a $4 bag works out to $54. Add the delivery fee to the bulk price, then divide by the yards you order.
Price is not the only difference. A bulk load needs a drop spot on firm ground close to the work, a tarp if rain is coming, and a lot of wheelbarrow trips. Bags go through a side gate, stack neatly and keep until you are ready. Spread a bulk pile of mulch or compost soon after delivery: a dense heap that cannot breathe turns sour and can scorch the plants it is spread around.
What a cubic yard weighs, and why it varies
Weight per yard depends on the material first and its water content second. A yard of sand weighs several times a yard of wood mulch, and the same soil weighs more wet than dry.
| Material | Pounds per cubic yard | Range | kg per m³ |
|---|---|---|---|
| Topsoil | 2,360 (1.18 tons) | 2,073–2,941 | 1,400 |
| Compost | 1,150 (0.58 tons) | 1,053–1,150 | 682 |
| Wood mulch | 473 (0.24 tons) | 243–530 | 281 |
| Sand | 2,800 (1.4 tons) | 2,587–3,093 | 1,661 |
| Gravel | 2,600 (1.3 tons) | 2,410–2,950 | 1,543 |
| Concrete | 4,000 (2 tons) | 3,780–4,080 | 2,373 |
Loose, as delivered; moisture moves soil, compost and mulch the most. Wood mulch is the roughest figure.
Four things move these figures:
- Water. Damp loam weighs about 14% more than dry loam, and wet, muddy loam about 40% more. Wet sand runs about 20% heavier than dry sand, and freshly chipped green wood weighs about twice as much as the same chips dried.
- Organic matter. Compost and mulch are mostly organic matter, air and water, which is why they weigh a fraction of mineral soil.
- Loose or in place. Soil swells when it is dug: topsoil loosened from the ground takes up about 1.5 times the space it filled in place, then settles back as it is spread, watered and walked on. The table gives loose, as-delivered weights.
- The individual load. Published densities for a single material carry about 10% of natural variation either way, so ask your supplier for its own weight per yard or the weight on the scale ticket.
That swell also sets how much dirt it takes to fill a hole or raise a low spot. Fill arrives loose and shrinks as it is placed and compacted, so order by loose volume. Allow about 1.5 loose yards of topsoil for every yard of ground it replaces, and more if you compact it hard.
To convert, divide pounds by 2,000 for US short tons, or kilograms by 1,000 for metric tonnes; one short ton is 907 kg. A single cubic yard of sand or wet topsoil weighs well over a ton, so check the payload rating of the truck or trailer before you load bulk material yourself. Stone weighs differently by type and size, and the gravel calculator weighs pea gravel, crushed stone and river rock individually.
Ordering ready-mix concrete, and how much extra
Order 4 to 10% more ready-mix than the plan dimensions give, and use the top of that range for a small slab placed by hand.
The allowance covers losses you cannot see on a drawing. Ready-mix is sold by its fresh volume, and hardened concrete takes up about 2% less once air escapes and the paste shrinks. A subgrade that dips just 1/8 inch (3 mm) under a 4-inch (10 cm) slab leaves you 3% short, and forms bow outward under the weight of wet concrete. Running out mid-pour is far worse than leftovers, because the pour cannot sit and wait for another truck.
Here is a 20 by 20 foot (6.1 × 6.1 m) patio slab, 4 inches (10 cm) thick:
- Area. 20 × 20 = 400 square feet (37.2 m²).
- Volume. 400 × 4 ÷ 12 = 133.33 cubic feet.
- Cubic yards. 133.33 ÷ 27 = 4.94 cubic yards (3.78 m³).
- Order. 4.94 × 1.04 = 5.14 cubic yards at the low end; 4.94 × 1.10 = 5.43 at the high end.
- Weight. At the calculator's figure for normal-weight concrete, the slab weighs about 9.9 tons (9 tonnes) once placed.
The same slab from 80 lb (36 kg) bags takes 223 bags for the bare volume and 245 with 10% extra. That is 19,600 pounds (8,890 kg) of dry mix to lift, with about 6 pints (2.8 L) of water mixed into every bag. Bags suit post holes and small pads; a patio is a job for the truck.
Before you call the plant, sort out three things:
- Access. Truck mixers carry 8 to 12 cubic yards, so one truck covers this slab. Loaded, it weighs about 80,000 pounds (36,000 kg) and may not be able to cross loose ground, a curb or a garden path. Plan where the chute will reach and whether you need a pump or wheelbarrows.
- Climate. Concrete that will freeze in service needs air entrainment. Tell the producer the slab is outdoors in a freezing climate when you order.
- Base. A slab sits on a compacted gravel base, commonly 4 to 6 inches (10 to 15 cm). For a 4-inch slab, that puts the dig about 8 to 10 inches (20 to 25 cm) below the finished surface. Size that stone separately with the gravel calculator, choosing Crusher run / road base so the packing allowance is added.
How deep to spread each material
Start from the depth the job needs, not the depth that uses up a round number of yards; depth moves the order more than any other measurement.
| Job | Starting depth | Cubic yards per 100 sq ft |
|---|---|---|
| Mulch a bed | 3 in (7.6 cm) | 0.93 |
| Cover new grass seed | 0.25 in (0.6 cm) | 0.08 |
| Topsoil for a new lawn | 6 in (15.2 cm) | 1.85 |
| Compost for a bed | 2 in (5.1 cm) | 0.62 |
| Fill a raised bed | 12 in (30.5 cm) | 3.7 |
| Pour a concrete slab | 4 in (10.2 cm) | 1.23 |
The calculator's starting depth for each job, before any extra.
Mulch. Spread 2 to 4 inches (5 to 10 cm): shredded bark at 2 to 3 inches, coarse wood chips at 3 to 4. More is not better. On wet, poorly drained soil, an organic layer more than 2 inches (5 cm) deep can rot roots, and mulch heaped against trunks invites decay, so pull it back several inches from every stem. The mulch calculator runs the same numbers for mulch-only jobs.
Seed cover. The Cover new grass seed job is for new seed, which wants a thin blanket of soil, ⅛ to ½ inch (3 to 13 mm), enough to hide it without burying it. On a home lawn, raking the seed in is the usual alternative: drag a leaf rake lightly so most of the seed ends up under about ¼ inch (6 mm) of soil. If you are laying turf instead, the sod calculator counts the pieces.
Topsoil for a new lawn. Aim for at least 4 to 6 inches (10 to 15 cm) measured after the soil has been firmed. Loose soil settles after rolling and watering, so add 10 to 15% to the order; that is what the 15% extra option is for. Work about 2 inches (5 cm) of it into the top few inches of the subsoil first, so water and roots cross the join instead of stopping at a layer.
Compost worked into soil. Spread 1 to 2 inches (2.5 to 5 cm) and work it 4 to 6 inches (10 to 15 cm) into the ground. Let a soil test decide how much organic matter the ground needs. A layer thicker than 2 inches is hard to till in evenly, so if you need more, spread and till it in two passes.
Raised beds. Build the frame at least 6 to 12 inches (15 to 30 cm) high so most vegetables have room to root. Fill with roughly two-thirds topsoil and one-third compost: enter the bed once, then split the volume between the two. The guide to building a raised garden bed covers siting, frames, fill recipes and soil volumes in more detail.
Concrete slabs. Four inches is the usual thickness for a patio or walk. Bagged mix can be placed as thin as 2 inches (5 cm), but that is the product's minimum, not a patio thickness; slabs under heavier loads go to 6 inches (15 cm). For a patio laid in pavers instead, the paver calculator counts the pavers and sizes the base and sand.
Mistakes that waste money
Most bad orders come from a handful of slips, and each one is quick to check before you pay.
- Typing a depth in the wrong unit. A depth of 3 inches (7.6 cm) entered as 3 feet orders twelve times the material. Check the unit beside the depth box.
- Measuring a round bed as a square. A circle fills only 78.5% of the square drawn around it, so taping the width twice and multiplying over-orders by more than a quarter. Choose Circle and enter the diameter.
- Using one weight for everything. A tons-per-yard figure borrowed from sand overstates a load of wood mulch about sixfold, and one borrowed from mulch puts a sand delivery dangerously over a trailer's rating.
- Ordering concrete to the exact volume. The slab above, ordered at 4.94 yards, is likely to run out at the far corner; build the allowance into the order.
- Leaving a bulk load where it cannot be moved. Have the truck drop it on a tarp near the work, not across the only path to the backyard.
Before you order, sketch the beds, paths and patio in Sow's garden design studio and take your measurements from the plan.