Cubic yard calculator: feet and inches to yards

To calculate cubic yards, multiply length by width by depth, all in feet, and divide by 27. If the depth is in inches, divide it by 12 first, and if the area is a circle or a triangle, work out its square footage with the right formula before you multiply by the depth.

How to calculate cubic yards

The 27 is the part people forget. One cubic yard is a cube 3 feet long, 3 feet wide, and 3 feet tall, so every cubic yard holds 3 × 3 × 3 = 27 cubic feet. Once you have the volume in cubic feet, dividing by 27 turns it into the unit the loader scoops and the ticket bills.

Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27

There is also a shortcut worth taping to the counter, from Texas AgriLife Extension: square feet times depth in inches, divided by 324, gives you cubic yards in one step. The extension's own example is 100 square feet at 3 inches deep, which comes out to 0.93 cubic yards. It works because 324 is the 12 inches in a foot and the 27 cubic feet in a yard combined into one number.

Cubic yards = square feet × depth (inches) ÷ 324

The area formulas for the three shapes most beds and pads break into are length times width for a rectangle, 3.1416 times the radius squared for a circle (the radius is half the diameter), and base times height divided by 2 for a triangle.

Cubic yard calculator

Worked examples: rectangle, circle, and triangle

These match the calculator above, so you can check your own math against them.

Rectangle: a 12 by 12 foot area at 4 inches deep

Multiply the length by the width for the area: 12 × 12 = 144 square feet. Convert the depth: 4 inches is a third of a foot. Multiply area by depth: 144 × 4 ÷ 12 = 48 cubic feet. Divide by 27 and you have 1.78 cubic yards, which is 1.36 cubic meters for a customer who thinks in metric. If that area is a mulch bed, 4 inches is the top of the 2 to 4 inch range University of Illinois Extension recommends.

Circle: a round bed 10 feet across at 3 inches deep

This is your tree ring or round island bed. The radius is half the diameter, 5 feet, so the area is 3.1416 × 5 × 5 = 78.5 square feet. At 3 inches, a quarter of a foot, that is 19.6 cubic feet, and 19.6 ÷ 27 = 0.73 cubic yards, or 0.56 cubic meters. One thing worth passing along while you load it: Illinois Extension says to keep mulch at least 4 inches back from the trunk, because mulch piled against the bark and root flare is among the most common causes of tree decline, and it is better to hear that from the yard than from an arborist.

Triangle: a corner bed with a 20 foot base and 12 foot height at 3 inches

Corner beds are everywhere, and they are the shape people most often give up on. The area is base × height ÷ 2, so 20 × 12 ÷ 2 = 120 square feet. At a quarter foot deep that is 30 cubic feet, and 30 ÷ 27 = 1.11 cubic yards, or 0.85 cubic meters.

The three mistakes that wreck an estimate

Forgetting to convert inches to feet. This is the big one. Take that 12 by 12 foot area and enter the depth as 4 feet instead of 4 inches and you get 576 cubic feet, or 21.33 cubic yards, twelve times the right answer and the difference between a pickup load and a tri-axle parked on somebody's lawn. Whenever a number looks too big, check the depth first.

Dividing by 9 instead of 27. There are 9 square feet in a square yard, and that number sticks in people's heads, so they divide cubic feet by 9 and come out with three times too much material. Square yards are for carpet and sod. Cubic yards are 27, every time.

Giving up on odd shapes. Almost nobody's yard is one clean rectangle. Break the space into rectangles, circles, and triangles, run each one through the calculator, and add the cubic yards at the end, so an L-shaped bed becomes two rectangles and a kidney-shaped island becomes a close-enough circle.

Quick reference: cubic yards per 100 square feet

If you do this math often enough to memorize one column, make it this one. It is the extension shortcut worked out in advance, 100 times the depth divided by 324, along with how much area one cubic yard covers at each depth.

So when a landscaper calls and says "I've got about 400 square feet at 3 inches," you can answer before the call is over: four times 0.93 is 3.72 yards.

Cubic yards to cubic meters, for Canada and metric jobs

Same dirt, different paperwork. One cubic yard equals 0.764555 cubic meters, the factor in the U.S. Energy Information Administration's metric conversion table, so the 1.78 yard rectangle above is 1.36 cubic meters and 10 cubic yards is 7.65. If weight comes into it, one short ton of 2,000 pounds is 0.9071847 metric tonnes. The calculator shows cubic yards and cubic meters together, so nobody has to do conversion math with a customer waiting at the counter.

Cubic yards to tons is a different question

The cubic yard tells you volume and nothing else. What that volume weighs depends on the material, and even the published factors disagree. Stone Center, an Ohio stone yard, puts sand at 1.10 to 1.25 tons per cubic yard, while Kokosing's aggregates business uses 1.5 for sands, and published gravel figures run from about 1.25 to 1.7 tons depending on the stone and whose chart you read, with moisture, fines, and compaction moving every one of them. Treat any tons-per-yard factor as an estimate and the yard's scale ticket as the record.

Our tons to cubic yards guide lays out the weight factors by material and source, the gravel calculator turns this same volume math into tons for stone, and the mulch and topsoil calculator turns it into bags and loader buckets. Mulch is sold by volume, so with mulch, yards are the whole conversation.

How this plays out at the counter

For a supply yard, this calculation is the first thirty seconds of a sale. A landscaper rattles off dimensions from the job site, usually in feet with a depth in inches, and the counter converts it, quotes it, and rings it before the truck finishes backing up to the pile.

Two habits make that go smoothly. First, quote the decimal the math gives you and then talk through the rounding out loud, because the job needs 1.78 yards but the loader bucket does not measure in hundredths, and the customer should know whether the ticket says 1.78 or a full bucket. Second, write the measurements and the depth on the ticket ("12 by 12, 4 inches, customer's measurement"), because when a contractor runs a half yard short on Friday afternoon, that note settles who measured what faster than any argument. If you also sell by weight, our guide to scale tickets for bulk material yards covers what belongs on that ticket.

Where Rundoo fits

Rundoo is the AI-first POS for independent supply stores, and bulk material sells in whatever units of measure you set up, with decimal quantities switched on per product, so 1.75 yards of mulch rings as 1.75 yards instead of forcing a whole number. You can schedule the delivery from the sale and the driver sees the stop in the Staff App, landscaper pricing tiers apply on every line, and charge accounts run their own statements. Rundoo does not connect to a scale, so a weighed load goes on the sale from the scale ticket. For how units of measure work across the rest of the store, see buy by the roll, sell by the foot, and if you run lumber alongside the bulk pile, the board foot calculator covers that side of the fence.