How to Use the Cubic Yard Calculator
- Choose your units. USA mode uses feet and inches and gives cubic yards, tons and bags. UK mode uses metres and millimetres and gives cubic metres, tonnes and bulk bags.
- Pick the shape of the area: rectangle, circle or triangle. If you already know the area, choose "Known area".
- Enter the measurements and the depth. Depth is the most important number: an extra inch on a 3-inch layer adds a third to your order.
- Choose the material. This sets the weight per cubic yard, the bag size, and a sensible allowance for settling.
- Add more areas if your project has several beds or sections. The calculator totals them.
- Enter a price per cubic yard, ton or bag (optional) to see the cost.
How to Calculate Cubic Yards
A cubic yard is a cube 3 feet wide, 3 feet long and 3 feet deep, which is 27 cubic feet. To find cubic yards:
Depth is usually measured in inches, so divide it by 12 first. Put together:
For other shapes, work out the area first, then multiply by the depth:
- Circle: area = 3.1416 × radius². A round bed 12 feet across has a radius of 6 feet and an area of 113 square feet.
- Triangle: area = base × height ÷ 2.
- Irregular areas: split them into rectangles, circles and triangles, then add the results.
In metric, it's simpler: cubic metres = length (m) × width (m) × depth (m). A depth of 75mm is 0.075 m. One cubic yard is 0.765 cubic metres, and one cubic metre is 1.308 cubic yards.
Worked example: mulch bed
A flower bed 20 feet by 10 feet, mulched 3 inches deep:
- 20 × 10 × 3 ÷ 324 = 1.85 cubic yards (50 cubic feet)
- In 2-cubic-foot bags: 50 ÷ 2 = 25 bags
- With 10% extra for settling: about 2 cubic yards bulk
Worked example: topsoil for a new lawn
The same 20 × 10 ft area with 4 inches of topsoil:
- 20 × 10 × 4 ÷ 324 = 2.47 cubic yards
- At about 1.1 tons per cubic yard: 2.7 tons
Worked example (UK): gravel path
A path 10 m long and 1 m wide, with gravel 50mm deep:
- 10 × 1 × 0.05 = 0.5 m³
- At 1.7 tonnes per m³: 0.85 tonnes, which is one 850kg bulk bag
How Far Does a Cubic Yard Go?
One cubic yard covers this many square feet at each depth:
| Depth | Area covered by 1 cubic yard | Typical use |
|---|---|---|
| 1 inch | 324 sq ft | Top-dressing a lawn |
| 2 inches | 162 sq ft | Topping up existing mulch |
| 3 inches | 108 sq ft | New mulch beds, decorative gravel |
| 4 inches | 81 sq ft | Topsoil for new lawn, gravel driveways |
| 6 inches | 54 sq ft | Raised beds, base for pavers |
Metric equivalent for 1 cubic metre: 40 m² at 25mm, 20 m² at 50mm, 13.3 m² at 75mm, 10 m² at 100mm, and 6.7 m² at 150mm.
Recommended Depths by Material
| Material and job | USA depth | UK depth |
|---|---|---|
| Wood mulch or bark in beds | 2–3 in | 50–75mm |
| Mulch around trees (keep it off the trunk) | 2–4 in | 50–100mm |
| Topsoil for a new lawn | 4–6 in | 100–150mm |
| Topsoil top-dressing an existing lawn | ¼–½ in | 5–10mm |
| Raised vegetable beds | 8–12 in | 200–300mm |
| Decorative gravel or pea gravel | 2–3 in | 30–50mm |
| Gravel driveway (top layer over a base) | 3–4 in | 40–50mm |
| Crushed stone base under pavers | 4–6 in (patio), 8–12 in (driveway) | 100mm (patio), 150mm+ (driveway) |
| Sand bedding under pavers | 1 in | 25–30mm |
| Concrete slab | 4 in | 100mm |
More mulch is not better: beyond about 4 inches it can starve roots of air and hold too much moisture against stems.
Converting Cubic Yards to Tons
Suppliers often sell landscaping materials by weight, so you'll need to convert. Weight depends on the material and how wet it is:
| Material | Tons per cubic yard (US) | Tonnes per cubic metre (UK) |
|---|---|---|
| Wood mulch / bark | 0.3 (about 600 lb) | 0.36 |
| Compost | 0.6 | 0.71 |
| Topsoil (dry) | 1.1 | 1.31 |
| Sand (dry) | 1.35 | 1.60 |
| Crushed stone / MOT Type 1 (loose) | 1.35 | 1.60 |
| Pea gravel / decorative gravel | 1.4 | 1.66 |
| River rock | 1.4 | 1.66 |
| Asphalt (compacted) | 1.96 | 2.33 |
| Concrete (wet) | 2.0 | 2.37 |
Tons = cubic yards × tons per cubic yard. For example, 3 cubic yards of gravel weighs about 3 × 1.4 = 4.2 tons.
Most UK builders' merchants use about 1.7 tonnes per m³ for gravel, and sell it in 850kg bulk bags. A bulk bag of gravel covers about 10 m² at 50mm deep. Bark and topsoil are usually sold by volume instead, in bags of around 0.7–1 m³, so check the label.
If you're paving a driveway, the Asphalt / Tarmac Calculator handles both the asphalt and the stone base. For concrete, the Concrete Calculator also works out bag counts and mix quantities.
Bags vs Bulk: Which Is Cheaper?
Bagged material is convenient for small jobs but adds up quickly. Common bag sizes:
- Mulch: 2 cubic feet per bag, so 13.5 bags = 1 cubic yard.
- Topsoil and garden soil: 0.75 or 1 cubic foot, so 27–36 bags per cubic yard.
- Sand and gravel: 0.5 cubic feet (about 50 lb), so 54 bags per cubic yard.
- UK: 20–25kg bags of gravel or sand cover roughly 0.25–0.4 m² each at typical depths; around 40 of them make one bulk bag.
As a rough guide, once you need more than about 1–2 cubic yards, bulk delivery is usually cheaper even after the delivery fee. In the USA, bulk topsoil typically costs about $10–$50 per cubic yard, plus a delivery fee that often runs $80–$170. For a single bed, bags save you the delivery charge and a pile on the driveway.
Allow for Settling and Compaction
Loose materials take up less space once they settle or are compacted. Order a little more than the exact volume:
- Mulch, bark and compost: add 10–15%. They settle and break down.
- Topsoil: add 10–20%, more if you'll firm it with a roller.
- Gravel, crushed stone and sand used as a base: add 15–25% when you're compacting with a plate compactor, because the material compresses.
- Decorative gravel: add 5–10% for uneven ground.
- Concrete: add 5–10% for spillage and uneven excavation.
The calculator includes a default allowance for each material, and you can change it.
Tips for Measuring Accurately
- Measure depth in several places. Excavations and old beds are rarely level. Use the average.
- Measure the area you'll actually fill, not the whole garden. Subtract paths, sheds and planted areas.
- Round up, not down. Running short and paying for a second delivery costs more than a few extra bags.
- Check the delivery access. A full truck of material can't always reach a back garden, and a tipper truck needs firm ground.
- Ask how the supplier measures. Some quote by the ton, others by the cubic yard or "per scoop" (often about half a yard).
Frequently Asked Questions
How do I calculate cubic yards?
Multiply length by width by depth in feet, then divide by 27. If the depth is in inches, multiply length × width × depth (inches) and divide by 324.
How many square feet does a cubic yard cover?
At 3 inches deep, one cubic yard covers 108 square feet. At 2 inches, it covers 162 square feet, and at 4 inches, 81 square feet.
How many bags of mulch are in a cubic yard?
13.5 bags of 2 cubic feet. For 3-cubic-foot bags, it's 9 bags.
How much does a cubic yard of topsoil weigh?
About 1 to 1.1 tons (2,000–2,200 lb) when dry, and up to about 1.5 tons when wet.
How much does a cubic yard of gravel weigh?
About 1.4 tons (2,800 lb). Crushed stone and sand are similar, about 1.35 tons.
How many cubic yards of mulch do I need?
Multiply the bed's length and width in feet by the depth in inches and divide by 324. A 20 × 10 ft bed at 3 inches needs 1.85 cubic yards, or about 2 with settling.
How much does a cubic yard of dirt cost?
In the USA, bulk fill dirt typically costs about $5–$18 per cubic yard and screened topsoil about $10–$50, plus a delivery fee that often runs $80–$170. Prices vary a lot by region and quality, so get a local quote and ask whether delivery is included.
Should I order by the yard or by the ton?
Use whichever unit your supplier quotes, and convert with the weight table above. Wet material weighs more, so a ton of wet topsoil gives you less volume than a ton of dry.
How do I convert cubic yards to cubic metres?
Multiply by 0.765. To go from cubic metres to cubic yards, multiply by 1.308.
How many tonnes of gravel do I need in the UK?
Multiply length × width × depth in metres to get cubic metres, then multiply by 1.7. A 20 m² area at 50mm needs 1 m³, or 1.7 tonnes, which is two 850kg bulk bags.
Need it delivered and spread?
Landscapers can supply, deliver and spread soil, mulch and gravel. Get local quotes before you order.