A 10 x 10 ft area 3 inches deep holds 25 cubic feet, or about 0.93 cubic yards: multiply length by width in feet, multiply by the depth in feet, and divide by 27, the cubic feet in a cubic yard.
Our cubic yard calculator does that math for a rectangle, a circle, or a triangle, takes the depth in inches or feet, and also gives cubic feet and cubic meters. Add a percentage if you want the order to include some extra.
Topsoil, gravel, and ready-mix concrete are commonly ordered by the cubic yard, so this is the number to have ready when you call a supplier.
How to measure for cubic yards
- Measure the length and width in feet. Convert inches to decimal feet by dividing by 12 (6 in is 0.5 ft). For an odd-shaped area, split it into rectangles, circles, and triangles, run each one, and add the cubic yards. If you already know the area in square feet, enter it as the length and 1 as the width.
- For a circle, measure the diameter, straight across through the center. The calculator halves it to get the radius, and the width field is not used.
- For a triangle, measure the two sides that meet at the square corner. If no corner is square, measure one side as the base and the distance from that side to the opposite point, square to the base, as the height.
- Measure the depth and pick the unit. Choose inches for a layer such as mulch, topsoil, gravel, or a slab, and feet for a hole or a deep fill. If the depth changes across the area, take several readings and use their average.
- Decide on extra. Leave it at 0 for the exact volume, or add a percentage for compaction and spills (see the section on extra below).
The cubic yard formula
- Area (sq ft): rectangle = length × width; circle = 3.1416 × radius × radius (radius = diameter ÷ 2); triangle = base × height ÷ 2
- Depth in feet = depth in inches ÷ 12
- Cubic feet = area × depth in feet
- Cubic yards = cubic feet ÷ 27; cubic meters = cubic feet × 0.0283
- With extra: multiply by 1 + (extra % ÷ 100), so 10% extra is × 1.1
A cubic yard is a cube 3 ft on each side, and 3 × 3 × 3 = 27 cubic feet; NIST Handbook 44 lists 27 cubic feet to the cubic yard. The area formulas are the ones in University of Minnesota Extension's math guide for gardeners. Clemson's Home & Garden Information Center gives a shortcut that skips the conversion to feet: square feet × depth in inches ÷ 324 = cubic yards, because 27 × 12 = 324.
Worked example (the calculator's default values)
A rectangle 10 ft long and 10 ft wide, covered 3 inches deep, with no extra:
- Area: 10 × 10 = 100 sq ft
- Depth: 3 ÷ 12 = 0.25 ft
- Volume: 100 × 0.25 = 25 cu ft
- Cubic yards: 25 ÷ 27 = 0.93 cubic yards, or 0.71 cubic meters
The calculator shows: "You need 0.93 cubic yards (25 cu ft)." and "Area: 100 sq ft (rectangle, 10 x 10 ft). 100 sq ft x 3 in (0.25 ft) = 25 cu ft. Divided by 27, that is 0.93 cubic yards, or 0.71 cubic meters." Clemson's shortcut agrees: 100 × 3 ÷ 324 = 0.93. Enter 10 as the extra and the result becomes "You need 1.02 cubic yards (27.5 cu ft) with 10% extra."
Second example: a round bed 12 ft across
The radius is 6 ft, so the area is 3.1416 × 6 × 6 = 113.1 sq ft. Choose Circle, enter 12 as the length and 4 in as the depth: "You need 1.40 cubic yards (37.7 cu ft)." Whatever is left in the width field is ignored.
Third example: a triangular corner bed
A bed in a square corner with sides of 10 ft and 8 ft has 10 × 8 ÷ 2 = 40 sq ft. At 3 in deep: "You need 0.37 cubic yards (10 cu ft)."
Fourth example: digging 3 feet deep
For a hole or a deep fill, switch the depth unit to Feet. A 10 x 10 ft area dug 3 ft deep gives "You need 11.11 cubic yards (300 cu ft)." That is the volume of the hole itself. As a check, a cube 3 ft on every side gives "You need 1.00 cubic yards (27 cu ft)."
Cubic yards by area and depth
Computed with the calculator's math, no extra included. Find your area, then read across to your depth. The last row shows how many square feet one cubic yard covers at each depth.
| Area | 1 in | 2 in | 3 in | 4 in | 6 in | 12 in |
|---|---|---|---|---|---|---|
| 50 sq ft | 0.15 | 0.31 | 0.46 | 0.62 | 0.93 | 1.85 |
| 100 sq ft | 0.31 | 0.62 | 0.93 | 1.23 | 1.85 | 3.70 |
| 200 sq ft | 0.62 | 1.23 | 1.85 | 2.47 | 3.70 | 7.41 |
| 300 sq ft | 0.93 | 1.85 | 2.78 | 3.70 | 5.56 | 11.11 |
| 500 sq ft | 1.54 | 3.09 | 4.63 | 6.17 | 9.26 | 18.52 |
| 1,000 sq ft | 3.09 | 6.17 | 9.26 | 12.35 | 18.52 | 37.04 |
| 1 cubic yard covers | 324 sq ft | 162 sq ft | 108 sq ft | 81 sq ft | 54 sq ft | 27 sq ft |
Clemson's fact sheet puts it the same way: one cubic yard covers 324 sq ft at 1 inch. UConn Extension estimates that 12 cubic yards cover about 1,000 sq ft at 4 inches, in line with the 12.35 in the table.
Cubic yards, cubic feet, and cubic meters
| Unit | Cubic yards | Cubic feet | Cubic meters |
|---|---|---|---|
| 1 cubic yard | 1 | 27 | 0.765 |
| 1 cubic foot | 0.037 | 1 | 0.0283 |
| 1 cubic meter | 1.308 | 35.31 | 1 |
NIST defines the foot as exactly 0.3048 meter and the yard as exactly 0.9144 meter, so a cubic yard is 0.9144 × 0.9144 × 0.9144 = 0.7646 cubic meters, which Handbook 44 rounds to 0.765. The calculator uses the exact factor. A cubic yard is also 46,656 cubic inches (27 × 1,728), and University of Minnesota Extension lists it as 202 US gallons.
From cubic yards to what you buy
UConn Extension notes that topsoil is generally sold by the cubic yard and that the minimum amount commonly delivered is 3 to 6 yards. Stoneco says gravel is typically measured in cubic yards, and Concrete Network reminds buyers that one cubic yard of ready-mix concrete is 27 cubic feet. When you buy by the bag, by the ton, or with a waste allowance, a material calculator takes the next step:
- Gravel and crushed stone: if your supplier quotes by the ton, the gravel calculator converts cubic yards to tons with a weight per cubic yard you can change.
- Sand: the sand calculator adds the weight of dry or wet sand in pounds or tons and counts 50 lb bags.
- Topsoil and fill: the topsoil calculator adds bag counts for 0.75 and 1 cu ft bags.
- Mulch: the mulch calculator counts 2 and 3 cu ft bags.
- Concrete: the concrete calculator adds extra for waste and counts 60 and 80 lb premix bags.
This calculator doesn't give a weight, because weight depends on the material. Ask the supplier for the weight per cubic yard of the exact product.
Bags per cubic yard
Divide 27 by the bag size printed on the label:
| Bag size | Bags per cubic yard |
|---|---|
| 0.5 cu ft | 54 |
| 0.75 cu ft | 36 |
| 1 cu ft | 27 |
| 1.5 cu ft | 18 |
| 2 cu ft | 13.5 |
| 3 cu ft | 9 |
For bags, work from cubic feet and round up: the default 25 cu ft job takes 25 ÷ 2 = 12.5, so 13 bags of 2 cu ft.
How much extra to order
The calculator gives the exact geometric volume, and loose material doesn't always stay that size. Stoneco notes that compaction can reduce gravel volume by as much as 20 percent. To still reach the full depth after a 20 percent loss, divide by 0.8, which is the same as 25 percent extra: the default job becomes "You need 1.16 cubic yards (31.3 cu ft) with 25% extra." Stoneco also suggests ordering slightly more than you think you need, such as rounding up to the next whole cubic yard.
For concrete, Concrete Network says never to order the exact amount, and its rule of thumb is to add 1/4 inch to the slab thickness. For a 10 x 10 ft slab, that moves the order from 1.23 cubic yards at 4 in to 1.31 at 4 1/4 in (enter 4.25). The concrete calculator starts with 10 percent extra for waste.
Tips and common mistakes
- Mixing inches and feet. A quarter foot typed as 0.25 with the unit set to Inches gives 0.08 cubic yards instead of 0.93, twelve times too little. Typing 3 with the unit set to Feet gives 11.11, twelve times too much.
- Using the diameter as the radius. For a circle, the radius is half the distance across. Mixing them up quadruples the area: a 12 ft circle at 4 in would come out at 5.59 cubic yards instead of 1.40.
- Confusing square yards and cubic yards. A square yard is 9 sq ft of area; a cubic yard is 27 cu ft of volume.
- Measuring the depth in one spot. On uneven ground, average several readings.
- Ignoring what is already there. If an inch of old mulch or gravel remains, enter only the depth you are adding.
- Leaving in areas that won't be covered. Subtract patios, walks, and other hardscape before you calculate.
Frequently asked questions
How do I calculate cubic yards?
Multiply the length by the width in feet, multiply by the depth in feet (inches ÷ 12), and divide by 27. A 10 x 10 ft area 3 inches deep is 100 × 0.25 = 25 cu ft, or 0.93 cubic yards.
How many cubic feet are in a cubic yard?
27, because a cubic yard is a cube 3 ft on each side (3 × 3 × 3). It is about 0.765 cubic meters.
How many square feet does a cubic yard cover?
Divide 324 by the depth in inches: 324 sq ft at 1 inch, 162 at 2 inches, 108 at 3 inches, 81 at 4 inches, and 54 at 6 inches.
How do I calculate cubic yards for a circle?
Multiply 3.1416 by the radius squared for the area, then by the depth in feet, and divide by 27. A circle 12 ft across, 4 inches deep, is about 1.40 cubic yards.
How many bags make a cubic yard?
Divide 27 by the bag size: 13.5 bags of 2 cu ft, 9 bags of 3 cu ft, 27 bags of 1 cu ft, or 36 bags of 0.75 cu ft.
How many cubic yards are in a cubic meter?
About 1.308. Going the other way, a cubic yard is about 0.765 cubic meters, because NIST defines the yard as exactly 0.9144 meter.
Sources
- NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement (PDF)
- University of Minnesota Extension: Math for gardeners: Formulas you can use
- Clemson Cooperative Extension, Home & Garden Information Center: Mulch
- UConn Extension: Purchasing Topsoil (PDF)
- Stoneco: How to Calculate How Much Gravel You Need
- Concrete Network: Concrete Calculator and Ordering Tips
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