Square Yards Calculator

What a square yard is, and the exact number behind it

A square yard is a square with sides one yard long, and one yard is 3 feet, so the area works out to 3 x 3 = 9 square feet. In inches that is 36 x 36 = 1,296 square inches. The yard itself is pinned to the metric system: the NIST Handbook 44, Appendix B defines 1 yard as exactly 0.9144 meter, a definition set in 1959, which makes one square yard equal to 0.83612736 square meters.

The NIST Guide to the SI, Appendix B.9 lists the same square yard factor as 8.361 274 E-01 square meters and the cubic yard as 7.645 549 E-01 cubic meters. Those two factors cover most of what a yard-based project needs, because area comes from squaring a length and volume comes from cubing it.

Three conversions run this page:

• square yards = square feet / 9
• square feet = square yards x 9
• cubic yards = square feet x depth in inches / 324

The 324 in the last line is 9 x 12 x 3, the number of square feet one cubic yard covers at a single inch of depth. Divide 324 by the depth and you get the coverage of one yard of any loose material: 324 sq ft at 1 inch, 162 at 2 inches, 108 at 3 inches, 81 at 4 inches. The FHWA unit conversion table rounds the square yard to 0.836 square meters, the same factor to three decimals.

Measure length and width, then multiply

For a rectangle, the whole job is one multiplication. A patio 12 feet by 18 feet is 12 x 18 = 216 square feet, and 216 / 9 = 24.00 square yards. The same patio is 20.07 square meters, and if you measured it as 4 yards by 6 yards, the answer is the same 24.00 square yards, because 4 x 6 = 24 and the yard is already the unit you want.

Two measurements in different units are the common slip. A 12 foot 6 inch side is 12.5 feet, not 12.6, because 6 inches is half a foot. Enter 12.5 and 18 into the calculator above and you get 25.00 square yards instead of 24.00, a difference of one square yard, which at carpet prices is real money.

An L shaped yard splits into rectangles that you add together. A larger example: a driveway 30 feet by 40 feet is 1,200 square feet, or 133.33 square yards, and 111.48 square meters. Compare that with a 15 by 20 foot room, which is 300 square feet, 33.33 square yards, and 27.87 square meters. Both figures come straight out of the calculator above with the measurements in feet.

Square yards, square feet, square meters and acres

Different sellers quote different units for the same patch of ground, and the price per unit changes with the unit. Here is the ladder, with a few landmarks on it.

The acre sits at 4,840 square yards because it is 43,560 square feet and 43,560 / 9 = 4,840. A square mile holds 3,097,600 square yards, which is 640 acres. Going the other way, 100 square yards is a bit under 84 square meters, so a metric quote of 84 square meters describes about the same floor as 100.46 square yards.

Costs convert the same way, and this is where people get burned. A carpet quoted at $6.50 per square yard costs $0.72 per square foot, because 6.50 / 9 = 0.7222. A quote of $6.50 per square foot describes a floor nine times as expensive. Check the unit on the price tag before you check the price.

Materials that get sold by the square yard

Three materials in particular get quoted in square yards, and each one has its own habit of measuring.

Sod. The Purdue Extension guide to establishing a lawn from sod notes that vendors typically sell sod by the square yard, that one pallet holds about 50 square yards, or 450 square feet, and that you should order about 10 percent more than the measured area to cover cutting and fitting. Mississippi State Extension puts pallets in the same 450 to 500 square foot range and suggests roughly 5 percent extra for a straightforward yard. Purdue also figures sod at 35 to 40 pounds per square yard, so a 24.00 square yard lawn weighs roughly 840 to 960 pounds on the pallet.

Carpet. Carpet comes on rolls 12 feet wide, which is 4 yards, and one linear yard of that roll covers 12 square feet. A 12 by 18 foot room therefore takes 6 linear yards of the roll, and 6 x 4 = 24.00 square yards. A 15 by 20 foot room is 33.33 square yards on the floor, and because the roll is only 12 feet wide the leftover strip along the 15 foot side is waste you pay for anyway.

Concrete. State highway departments price sidewalk and driveway work by area. The Alabama DOT standard specifications list concrete sidewalk and driveway pay items per square yard, with the accepted area computed in square yards. Ready mix, on the other hand, is sold by the cubic yard, which is where the depth calculation in the next section comes in.

From square yards to cubic yards when you add a depth

Area tells you how much ground you cover. Depth tells you how much material fills it, and depth is measured in inches while material is sold in cubic yards. One cubic yard is 27 cubic feet, and spread an inch deep it covers 324 square feet, so the cubic yards you need are:

cubic yards = square feet x depth in inches / 324

For the 216 square foot patio at 4 inches of concrete, that is 216 x 4 / 324 = 2.67 cubic yards. Add a 10 percent waste factor and the order becomes 2.93 cubic yards. The driveway example runs the same way: 1,200 square feet at 3 inches is 1,200 x 3 / 324 = 11.11 cubic yards, and 11.67 cubic yards with 5 percent waste.

The USDA NRCS mulching guide calls a 2 inch depth of organic mulch the rule of thumb for holding moisture and keeping weeds down, with finely textured shredded hardwood capped at 3 inches and coarse pine bark nuggets allowed up to 4 inches. The same guide prints a coverage chart that lists 162 square feet per cubic yard at 2 inches and 108 at 3 inches, which matches the 324 formula to the digit.

For the patio bed that means 216 square feet at 2 inches needs 216 / 162 = 1.33 cubic yards of mulch. At 4 inches, the coarse bark maximum, it needs 216 / 81 = 2.67 cubic yards, the same figure as the concrete slab because the depth matches.

How much to buy: the waste factor

Measured area is the floor of the order, not the order. Cuts around edges, overlaps at seams and the piece that tears during handling all come out of the same delivery, so every trade adds a waste percentage before ordering. The calculator above applies your waste factor to both the square yards and the cubic yards, and prices the order on the waste-adjusted figure.

Worked on the patio numbers: 24.00 square yards at 10 percent waste is 26.40 square yards to order. At a carpet price of $6.50 per square yard that comes to $171.60, and at $18.50 per square yard the same 26.40 square yards runs $488.40. The 33.33 square yard room at $22.00 per square yard, with the same 10 percent, prices at $806.67. Each price comes from the waste-adjusted quantity, which is what the invoice will say.

Suppliers round on their side too. Ready mix concrete sells in quarter yard steps, sod sells by the whole pallet, and carpet retailers charge for the full linear yard of the roll. Round up to the unit your supplier sells in, and let the waste factor absorb the remainder rather than trying to buy a partial pallet.

Measuring mistakes that cost money

Most bad yardage orders trace back to one of five habits, and all five are cheap to avoid.

• Mixed units. One side in feet and the other in yards multiplies the answer by 3. A 4 by 6 yard patio is 24.00 square yards; the same patio measured as 12 by 6 feet is 8 square yards. Convert before you multiply.
• Inches left as decimals. 12 feet 6 inches is 12.5, not 12.6. Half of the measurement mistakes on orders come from that one line.
• Area measured at the top of a slope. A sloped bed has more surface than its footprint, so measure along the slope for materials that lie on the ground.
• Square and cubic mixed up. A cubic yard is volume and a square yard is area. Saying cubic when you mean square on a carpet order triples the price by accident.
• No waste factor. Ordering 24.00 square yards for a 24.00 square yard lawn leaves nothing for the cuts, and a second delivery costs more than the slack would have.

One check catches most of them: multiply the two measurements, divide by 9, and see whether the result is close to the number of 3 foot paces you would take across the space. A patio you cross in 4 paces by 6 paces should land near 24.00 square yards, and a number far from that means a unit slipped somewhere.

For big areas, break the plot into rectangles, calculate each one, and add them. A yard with a house, beds and a driveway subtracts, so measure the grass area rather than the lot: the Purdue sod guide figures turf area by taking the lot, removing the house footprint, and working from what is left.

A patio job from tape measure to delivery

Here is the whole workflow on one set of numbers, the 12 by 18 foot patio, using the calculator above at each step.

Step one, measure. Both sides in feet: 12 and 18. Area is 216.00 square feet.

Step two, square yards. 216 / 9 = 24.00 square yards, which is 20.07 square meters if the supplier quotes metric.

Step three, depth. A 4 inch concrete slab needs 216 x 4 / 324 = 2.67 cubic yards. The same area as a 2 inch mulch bed needs 1.33 cubic yards, and as a 3 inch gravel path it needs 2.00 cubic yards.

Step four, waste. Ten percent on the area gives 26.40 square yards to order, and on the concrete it gives 2.93 cubic yards. Order 3.0 cubic yards from the ready mix plant, since quarter yard steps run up from 2.93.

Step five, price. At $6.50 per square yard the 26.40 square yards invoice at $171.60. Per square foot that is $0.72, and per square meter about $7.77, because 26.40 square yards is 22.08 square meters and 171.60 divided by 22.08 gives that figure.

The same five steps work for a lawn, a gravel path or a bed of topsoil. Only the depth and the unit the supplier sells in change, and the calculator above keeps the arithmetic in one place.