If you are ordering gravel, soil, mulch, sand or concrete, you will be asked for a quantity in cubic yards. It is a unit of volume, and the math is short. To calculate cubic yards, multiply length and width in feet by depth in inches, then divide by 324. Below are checked examples and a free conversion chart.
What a cubic yard is
A cubic yard is a cube 3 feet wide, 3 feet long and 3 feet tall. Three feet times three feet times three feet is 27, so one cubic yard is 27 cubic feet.1
The formula
- Measure length and width in feet.
- Measure depth in inches and divide by 12 to get feet.
- Multiply length x width x depth (all in feet) to get cubic feet.
- Divide by 27 to get cubic yards.
- Choose an allowance for your material and project; a single percentage does not fit every job.
Example 1: a garden bed
A bed is 20 feet long, 5 feet wide, and you want 3 inches of mulch. Depth is 3 / 12 = 0.25 feet. Volume is 20 x 5 x 0.25 = 25 cubic feet. Divide by 27 to get 0.93 cubic yards. With 10 percent extra that is 1.02 cubic yards, so order 1 cubic yard and check whether you need a little more.
Example 2: a gravel pad
A pad is 12 feet by 10 feet and 4 inches deep. Depth is 4 / 12 = 0.333 feet. Volume is 12 x 10 x (4 / 12) = 40 cubic feet. Divide by 27 for 1.48 cubic yards. Add 10 percent for 1.63 cubic yards. Gravel is often sold by the ton, so ask your supplier how many tons are in a cubic yard of the stone you chose, then use the gravel calculator.
Example 3: a round area
For a circle, area is 3.1416 x radius x radius. A round bed 10 feet across has a 5 foot radius, so area is 3.1416 x 5 x 5 = 78.5 square feet. At 3 inches deep that is 78.5 x 0.25 = 19.6 cubic feet, or 0.73 cubic yards.
Common mistakes
- Leaving depth in inches. Divide by 12 first.
- Forgetting extra for waste.
- Rounding down. It is better to round up to a convenient order size.
- Using the same ton conversion for every stone. It varies, so ask the supplier.
Quick check
One cubic yard covers 324 square feet at 1 inch deep, 108 square feet at 3 inches and 81 square feet at 4 inches. See the coverage cheat sheet for more depths.
Use the calculators to skip the arithmetic. Estimates only. Confirm quantities with your supplier.
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Square feet to cubic yards: the easy shortcut
Cubic yards = area in square feet x depth in inches / 324. The 324 is 12 x 27: divide by 12 to change inches to feet, then by 27 to change cubic feet to cubic yards. If your length and width are already measured in feet, multiply them to get area first. If the depth is already in feet, use area x depth / 27 instead.1
Square feet alone cannot tell you the yardage. A 500-square-foot area needs twice as much material at 4 inches as it does at 2 inches. Measure the planned depth, not just the surface. These are geometric volumes before any allowance for waste or compaction.
| Area (sq ft) | 2 in deep (yd³) | 3 in deep (yd³) | 4 in deep (yd³) | 6 in deep (yd³) |
|---|---|---|---|---|
| 100 | 0.62 | 0.93 | 1.23 | 1.85 |
| 200 | 1.23 | 1.85 | 2.47 | 3.70 |
| 300 | 1.85 | 2.78 | 3.70 | 5.56 |
| 500 | 3.09 | 4.63 | 6.17 | 9.26 |
| 1000 | 6.17 | 9.26 | 12.35 | 18.52 |
We calculated every cell from area x depth / 324. The 2-, 3- and 4-inch columns match CalculatorSoup’s published table.1
How many feet is a cubic yard?
A cubic yard contains 27 cubic feet, not 3 cubic feet. A yard is 3 feet long; a cubic yard has three dimensions: 3 x 3 x 3 = 27. If you mean linear feet, you need to say how wide and deep the material is. A cubic yard can make a 27-foot-long strip that is 1 foot wide and 1 foot deep, or a 54-foot-long strip that is 1 foot wide and 6 inches deep.
Cubic feet, bags and cubic yards
To change cubic yards to cubic feet, multiply by 27. To change cubic feet to cubic yards, divide by 27. For bagged material, divide the cubic feet needed by the volume printed on the bag, then round up to whole bags. Use volume, not bag weight: a 40-pound bag does not have one universal cubic-foot yield.
| Volume printed on bag | Exact bags per cubic yard | Whole bags to cover at least 1 yd³ |
|---|---|---|
| 0.5 cu ft | 54 | 54 |
| 0.75 cu ft | 36 | 36 |
| 1 cu ft | 27 | 27 |
| 1.5 cu ft | 18 | 18 |
| 2 cu ft | 13.5 | 14 |
| 3 cu ft | 9 | 9 |
For example, 1.5 cubic yards is 40.5 cubic feet. At 2 cubic feet per bag, 40.5 / 2 = 20.25 bags, so buy 21 whole bags before any extra allowance. CalculatorSoup publishes the same bags-per-yard conversion.1
How much extra should you order?
Keep the measured volume and the order allowance separate. CalculatorSoup suggests 5 to 10 percent for decorative mulch and topsoil grading, and 10 to 15 percent for gravel paths or paver bases. Those are estimating suggestions from a calculator publisher, not a promise that every material will shrink by that amount. Its concrete guidance is not fully consistent: its table says 5 percent, while its FAQ says 5 to 10 percent. Confirm an allowance with your ready-mix supplier rather than choosing a universal number.1
Multiply the base volume by 1 + allowance / 100. For the 1.48-yard gravel pad above, the unrounded calculation is 40 / 27 = 1.48148 yards. A 10 percent example allowance gives 1.62963 yards, or 1.63; a 15 percent allowance gives 1.70370 yards, or 1.70. Round only after calculating. A loose delivered yard and a compacted installed yard are not necessarily interchangeable. For grading, read our fill dirt guide before deciding on a compaction allowance.
Cubic yards are not tons
Yards measure volume; tons measure weight. If a seller quotes by the ton, multiply cubic yards by that product’s tons-per-yard figure. As an arithmetic example only, 2.5 yards at a stated 1.4 US tons per yard equals 3.5 US tons. Do not use that example density for every material. Moisture, particle size and the material change the conversion. Use our gravel tons-per-yard guide and ask the supplier which figure belongs to the product you are ordering.
Frequently asked questions
Does one cubic yard equal 9 square feet?
Only when it is 3 feet deep. A square yard is 9 square feet of area. A cubic yard is volume, so its coverage changes with depth. At 3 inches deep it covers 108 square feet; at 4 inches it covers 81. Do not exchange square yards and cubic yards without a depth.
How do I calculate an irregular yard?
Split it into rectangles, triangles and circles, calculate each area, then add them. Apply depth to the total if every section has the same depth. If depths differ, work out each section’s volume separately and add the volumes. Our irregular-yard measuring guide walks through that process.
Can I calculate material cost from cubic yards?
Yes. Multiply your order quantity by the supplier’s price per cubic yard, then add delivery, tax and any minimum-load fee separately. If the quote is per ton, first make the product-specific weight conversion. Confirm whether the quoted quantity is loose or compacted material so the price and yardage refer to the same thing.
Sources
- CalculatorSoup: Cubic Yards Calculator (volume formulas, coverage, bag conversions and estimating allowances; read October 6, 2026)