Cubic Yard Calculator
Find how many cubic yards of material a job needs. Choose the shape of your area (rectangle, circle or triangle), enter the dimensions in feet or metres, set the depth in inches or feet, and the calculator converts to cubic yards, cubic feet and cubic metres. Turn on the optional cost estimate to price out the job, or enable the waste allowance to get a safe order quantity.
Formula
Worked example
A 10 ft x 10 ft rectangular slab poured 4 inches deep: convert depth to feet (4 / 12 = 0.333 ft), then 10 x 10 x 0.333 = 33.33 ft3, and 33.33 / 27 = 1.23 cubic yards. Add 10% waste to get 1.36 yd3 and round up to order 2 yd3.
The cubic yard formula for any shape
A cubic yard is the volume of a cube that measures one yard (three feet) on every edge, so it equals 3 x 3 x 3 = 27 cubic feet. The general rule is: find the footprint area in square feet, multiply by the depth in feet, then divide by 27. This calculator handles the three most common footprints. For a rectangle, area = length x width. For a circle, area = pi x radius squared (enter the diameter and the calculator halves it for you). For a triangle, area = 0.5 x base x perpendicular height. If your project has an irregular shape, divide it into these simple pieces, calculate each one, then add the results.
Converting depth units and reading your result
Depth is almost always expressed in inches for slabs, driveways and landscape beds, because the numbers are small and easy to visualise: a 4-inch concrete slab, a 3-inch mulch top-dressing, a 6-inch gravel base. The formula needs feet, so inches are divided by 12 and centimetres by 30.48 before the multiplication happens. The outputs include cubic yards (the ordering unit in North America), cubic feet (useful for bagged materials) and cubic metres (for metric suppliers). The quantity multiplier lets you handle several identical footings or pad sections in a single calculation.
Waste allowance, bag count and cost estimate
No pour or fill is perfectly efficient. Ready-mix concrete can be lost to spills, uneven sub-grade and over-excavation; gravel and topsoil compact and settle; mulch blows or breaks down at the edges. A 10% waste allowance is a standard rule of thumb for most materials, 15% for compacted bases. Toggle on the waste allowance to see both the exact volume and a padded order quantity, then round up to the nearest amount your supplier sells. If you are buying bagged materials instead of a bulk delivery, use the bag count toggle to see how many bags of a given size cover the job. Finally, enter a price per cubic yard (bulk) to get a rough material cost. Delivery fees and labour are separate.
Common cubic yard reference guide
Concrete slabs for residential use are typically 4 inches deep (driveways sometimes 6 inches). Topsoil or garden beds work well at 6 inches for new plantings. Mulch is usually 2 to 3 inches. A gravel driveway base is commonly 4 to 6 inches, with a finished stone layer of 2 to 3 inches on top. One cubic yard of ready-mix concrete weighs roughly 4,000 lb (1.8 tonnes). One cubic yard of topsoil weighs about 2,000 lb (0.9 t). A standard concrete mixer truck holds 8 to 10 cubic yards, and most suppliers charge a short-load fee for orders under 3 to 5 cubic yards.
Coverage table: cubic yards for a 10 ft x 10 ft (100 ft2) area
| Depth | Common use | Cubic feet | Cubic yards | Order this many |
|---|---|---|---|---|
| 2 in | Light mulch top-up | 16.7 | 0.62 | 1 yd3 |
| 3 in | Standard mulch / decorative stone | 25.0 | 0.93 | 1 yd3 |
| 4 in | Concrete slab / topsoil bed | 33.3 | 1.23 | 2 yd3 |
| 6 in | Concrete driveway / gravel base | 50.0 | 1.85 | 2 yd3 |
| 8 in | Thick gravel sub-base | 66.7 | 2.47 | 3 yd3 |
| 12 in | Deep topsoil layer / raised bed | 100.0 | 3.70 | 4 yd3 |
| 18 in | Deep foundation fill | 150.0 | 5.56 | 6 yd3 |
Volume = 100 ft2 x depth in feet / 27. Use the quantity field for multiple identical sections.
Frequently asked questions
How many cubic feet are in a cubic yard?
There are 27 cubic feet in one cubic yard. A yard is three feet, so a cube one yard on each side measures 3 x 3 x 3 = 27 cubic feet. That is why the formula divides the cubic-foot volume by 27 to convert to cubic yards.
How do I calculate cubic yards for a circular area like a round patio or tree ring?
Select "Circle" from the shape menu, enter the diameter of the circle in feet (not the radius), then enter the depth. The calculator computes pi x (diameter / 2)^2 for the area, multiplies by depth, and divides by 27. For example, a 12 ft diameter circle at 3 inches deep is pi x 36 x 0.25 = 28.27 ft3, which is about 1.05 cubic yards.
How much extra material should I order?
Add about 5 to 10 percent on top of the calculated volume for soil, mulch and concrete, and 10 to 15 percent for compacted gravel or crushed stone. Toggle on the waste allowance above and set the percentage to get a safe order quantity automatically. The rounded-up figure accounts for the fact that most suppliers sell in whole or half-yard increments.
How do I convert square feet and a depth in inches to cubic yards?
Multiply the square footage by the depth in inches, then divide by 324. That shortcut works because 27 cubic feet per yard times 12 inches per foot equals 324. For example, 500 ft2 at 4 inches: 500 x 4 = 2000, then 2000 / 324 = 6.17 cubic yards. Alternatively enter the length and width in the rectangle mode with "Inches" selected for depth.
How many bags of concrete or topsoil equal one cubic yard?
It depends on the bag size. A 0.5 ft3 bag takes 54 bags to fill one cubic yard (27 ft3 / 0.5). A 0.6 ft3 bag takes 45 bags. An 80 lb ready-mix concrete bag covers about 0.6 ft3, so you need roughly 45 of them per cubic yard. Toggle on the bag count in the calculator, choose your bag size, and it will work out the exact number for your area.
How much does a cubic yard of material weigh?
Weight depends on the material. Ready-mix concrete is about 3,700 to 4,050 lb per cubic yard. Dry topsoil is roughly 1,800 to 2,200 lb. Dry gravel or crushed stone is around 2,700 to 3,000 lb. Mulch (dry) is 400 to 800 lb. These figures matter when checking whether a truck bed or dumper can carry the load safely.