How a yard is measured
A cubic yard is a box 3 feet on every side, 27 cubic feet, and a job is
measured as an area times a depth. The pages ask for the shape and its sides the
way a tape reads them, then the depth in inches: 4 is 4 inches,
1' is a foot, and a depth over 24 inches is questioned as feet in
the wrong box. A bed 10 by 12 feet and 3 inches deep is 30 cubic feet, 1.11
cubic yards. With the area already known, the same sum is square feet ×
inches ÷ 324: 100 square feet at 4 inches is 1.23 yards.
The quantity can also be a volume you were given — 100 cubic feet is 3.70 cubic yards — or a weight off a quarry ticket, which becomes yards once you say what it is: 10 short tons (2,000 lb) of crushed stone is 8 cubic yards. Turned round, 324 ÷ the depth is what one yard covers, 108 square feet at 3 inches, so those 10 short tons spread 3 inches deep cover 864 square feet.
The order is a step, and the step is what you pay for
Nobody delivers 1.11 yards. The pages round the order up once, after any waste, to the next quarter yard — 1.25 — or to the half or whole yard your supplier sells in. The price goes on the order, not on the hole: at $40 a yard the bed above is $50.00, not the $44.44 a popular calculator prints by multiplying 1.11 by $40. Whole yards, which another calculator advises, would order 2 — 0.75 more than the quarter-yard step.
Waste starts at zero, and that is a rule rather than an oversight: the yards are pure geometry, and the step already leaves a surplus. Type 10% and the bed becomes 1.22 yards — still an order of 1.25.
A yard weighs nothing until you say what it is
The material select is optional; without it the pages answer in cubic yards, cubic feet and cubic meters. Pick one and they weigh the yards at its loose figure: crushed stone about 2,500 lb a yard, topsoil and fill dirt about 2,360 lb, wood mulch 473 lb. Weights print in short tons (2,000 lb) and tonnes (1,000 kg) side by side, and the weight box refuses "tons" on its own, because the two are 10% apart: 10 tonnes of crushed stone is 8.82 cubic yards, not 8.
The weight decides how often a pickup goes back. A truck is limited by its bed and by its payload; the pages divide by both and say which won. A pad 10 by 12 feet and 4 inches deep in crushed stone is 1.48 yards and 3,704 lb. One bed of 2.27 yards holds it, but a 1,500 lb payload makes it 3 loads. Wood mulch runs the other way: the bed fills at about 1,074 lb, and the bed decides.
Where the numbers come from
The conversions are exact: a yard is defined as 0.9144 meters, so a cubic yard is 0.764555 cubic meters. The weights are the ones the gravel, mulch and fill dirt pages read: the Missouri DOT's maintenance tables for crushed stone and trap rock, a Federal Highway Administration report for #57 stone, the Minnesota Pollution Control Agency for sand, the NRCS soil quality guide for loam, and the EPA's volume-to-weight factors for wood chips. Pea gravel and river rock are suppliers' figures and crusher run borrows crushed stone's, so those three are estimates. So is fill dirt: the NRCS figure is the top of the ideal range for loam, dry in the ground — an upper bound for fill of unknown make-up.
The bed is the makers' own measure to the top of the sides — Ram's 6 ft 4 in box holds 61.3 cubic feet, Ford's 6.5 ft F-150 box 62.3 — and the smaller is kept. The 1,500 lb payload is an estimate, the low end for a full-size pickup; yours is on the sticker in the driver's door jamb. Zero waste and the 4 inch starting depth are conventions. Prices are reference estimates from the cluster that sells each material: $56 a yard of stone and a $95 delivery, so the cubic yards to short tons page opens at $655.00 for 10 yards; fill dirt at $9.50, the middle of a cost guide's range, with an $85 delivery borrowed from topsoil, so the fill dirt page opens at $120.63.
What these pages do not do
They do not sell bags. On the pages that start from a measured area, the links under the answer carry the shape to the gravel, mulch, topsoil and concrete pages, which do.
They do not compact anything, or allow for settling. Every weight is loose, as a truck delivers it — a compacted base is the gravel pages' question — and no source we would stand behind gives a settling figure for soil of unknown make-up, so fill gets nothing added unless you type your own into the waste box.
And they do not model a fill that runs from shallow to deep in one area. Split it into areas at their own depths; a page with more than one depth leaves out what a yard covers, because no single figure is true.