Gravel / Mulch / Topsoil Calculator
Area × depth gives the cubic yards (and cubic feet, tons, and bags) of gravel, mulch, topsoil, or sand you need, with a waste allowance. Free.
Gravel, Mulch and Topsoil Calculator
Enter the area you're covering and how deep, and this works out the cubic yards to order — plus the weight in tons and the number of bags — for gravel, mulch, topsoil, or sand. Bulk material is sold by the cubic yard, so getting the volume right saves money and trips.
How to Use the Gravel & Mulch Calculator
Measure the area
Enter the length and width of the space you're covering, in feet. For an irregular shape, break it into rectangles and add the results, or use the average dimensions.
Choose the depth
How deep you want the material, in inches. For mulch, Iowa State University Extension suggests 2–3 inches on heavy soils and 3–4 inches on well-drained sites around trees and shrubs. Commonly quoted figures for the rest are 2–4 inches for a gravel path or topdressing, 4–6 inches for a gravel driveway base, and 3–6 inches of topsoil for a new lawn or garden bed; confirm with your supplier or contractor.
Pick the material
Select gravel, sand, topsoil, or mulch — the choice sets the density used to estimate weight in tons, which matters for delivery and whether you can haul it yourself.
Order by the cubic yard
Bulk material is sold by the cubic yard, so the headline figure is what to order. The bag count helps if you're buying bagged product instead, and lets you compare the two: multiply the bag price by the count and set it against your supplier's delivered bulk price.
Buying Bulk Landscape Material Without Over-Ordering
Volume Is the Whole Game
Gravel, mulch, topsoil, and sand are all sold by volume — the cubic yard — so estimating a project is really a volume calculation. Multiply the area you're covering by the depth, convert to cubic yards, and you have your order. The only trick is the units: depth is naturally measured in inches but volume needs everything in the same unit, so the calculator converts depth to feet (dividing by 12) before multiplying by the area, then divides by 27 to turn cubic feet into cubic yards (since a cubic yard is 3 × 3 × 3 feet). A common mistake is forgetting that conversion and ordering far too much or too little. To make it concrete: a 240-square-foot bed at 3 inches deep needs 240 × 0.25 = 60 cubic feet, which is about 2.2 cubic yards — a single small delivery, not the ten-yard load a units slip-up might suggest.
Weight matters as much as volume when it comes to moving the material. The same cubic yard weighs very differently depending on what it is: gravel and sand are dense at roughly 1.3–1.4 tons per cubic yard, topsoil is around 1.1, and wood mulch is light at about half a ton. That's why three cubic yards of gravel — over four tons — needs delivery and a real plan to move, while three yards of mulch is a manageable afternoon with a wheelbarrow. The densities are reference values and shift with moisture (wet topsoil or mulch weighs noticeably more) and the exact product, so treat the tonnage as a guide for hauling and delivery, while the cubic-yard figure is what you actually order. Always round up and add a waste allowance: bulk material settles and compacts, beds are never perfectly even, and you can't easily top up a half-finished job once the delivery truck has gone.
"Bulk material is priced by the cubic yard but moved by the ton. Three yards of mulch is a wheelbarrow afternoon; three yards of gravel is four tons and a delivery truck — same volume, very different day."
Depths, Bags vs Bulk, and the Metric World
Choosing the right depth is where projects succeed or fail. For mulch, Iowa State University Extension suggests 2–3 inches of wood chips or shredded bark on heavy soils and 3–4 inches on well-drained sites, kept at least 6 inches away from tree trunks: too thin and weeds push through, too deep and heavy soils can waterlog and roots get less air. For the rest, the commonly quoted figures are 2–3 inches for a gravel walkway over a compacted base, 4–6 inches for a gravel driveway, often in layers of different stone sizes, and 3–6 inches of new topsoil for a lawn; your supplier or contractor can confirm what suits your ground. On the buying side, one cubic yard is about 13.5 two-cubic-foot bags, which is a lot of lifting, so for larger jobs compare the bag total with a delivered bulk price. For readers outside North America, the same logic applies in metric: bulk material is sold by the cubic metre, so compute your area in square metres, multiply by depth in metres, and order cubic metres (one cubic metre is about 1.3 cubic yards). Whatever the units, the recipe is the same: area times depth, converted to the selling unit, plus a margin for settling and waste.
A cubic yard is 27 cubic feet, and the material decides whether it weighs half a ton or well over one
Cubic yards = area (sq ft) × depth (in) ÷ 12 ÷ 27.
A cubic yard is 3 × 3 × 3 feet = 27 cubic feet.
The calculator uses reference weights: gravel/sand ~1.3–1.4 tons/yd³, topsoil ~1.1, mulch ~0.5. The PCA puts aggregate at about 1.0–1.5 tons/yd³ (1200–1750 kg/m³).
Mulch: 2–3 inches on heavy soils, 3–4 on well-drained sites (Iowa State University Extension).
A gravel driveway is commonly built 4–6 inches deep; a path 2–3 inches over a base.
Keep mulch at least 6 inches away from tree trunks to avoid cankers, rot and rodents.
Wet material (topsoil, mulch) weighs noticeably more than dry.
Always add a waste allowance — material settles and beds are uneven.
A typical bagged product holds 2 cubic feet, so ~13.5 bags = 1 cubic yard.
Metric: bulk is sold by the cubic metre (~1.3 cubic yards).
Frequently Asked Questions
- Multiply the area in square feet by the depth in inches, divide by 12 to get cubic feet, then divide by 27 to get cubic yards. For example, a 240 sq ft bed at 3 inches deep is 240 × 3 ÷ 12 = 60 cubic feet, or 60 ÷ 27 ≈ 2.2 cubic yards. Add a waste allowance for settling and uneven ground. This calculator does the conversion and also gives the weight and bag count.
- For mulch, Iowa State University Extension suggests 2–3 inches on heavy soils and 3–4 inches on well-drained sites around trees and shrubs — enough to suppress weeds and hold moisture without waterlogging the soil. Commonly quoted figures for the rest: about 2–3 inches for a decorative gravel path over a compacted base, 4–6 inches for a gravel driveway, ideally in layers, and 3–6 inches of new topsoil for a lawn or bed. Pick the depth for your specific use; the calculator turns it into the volume to order.
- It depends on the material. Gravel and sand are dense at roughly 1.3–1.4 tons per cubic yard, topsoil is about 1.1 tons, and wood mulch is light at around half a ton. So three cubic yards of gravel is over four tons (needs delivery and machinery to move), while three yards of mulch is manageable by wheelbarrow. Moisture increases the weight, so these are guides for planning delivery and hauling, not exact figures.
- Compare on price and handling. One cubic yard is around 13–14 two-cubic-foot bags, so for anything more than about a yard, check the bag price times the count against your supplier's delivered bulk price, and remember every bag has to be lifted and opened. Bags suit small touch-up jobs or sites that can't take a bulk delivery. The calculator shows both figures so you can make the comparison.
- A cubic yard is 27 cubic feet, so with the common 2-cubic-foot bag you'd need about 13.5 bags to equal one cubic yard (27 ÷ 2). Mulch sometimes comes in 3-cubic-foot bags (9 bags per yard) and some products in 1.5-cubic-foot bags (18 per yard). Set the bag size in the calculator to match your product. The math makes clear why bulk wins for large jobs — that's a lot of bags to lift and open.
- A 10% allowance is sensible for most projects. Bulk material settles and compacts as it's spread and walked on, ground is rarely perfectly even, and edges and spillage eat into the total. Running short is far more annoying than a small surplus, because you usually can't get the exact same product and color in a top-up load, and a second small delivery costs nearly as much as the first. Round up, and use any leftover to refresh the bed later.
- Break the space into simple rectangles, calculate each, and add the volumes — or for a curved bed, use the average length and average width to approximate a rectangle. For a circle, area is π × radius², so enter dimensions that give the same square footage. Slightly over-estimating an irregular shape is wise, since odd corners create more waste. The depth and material steps are unchanged; only the area input needs the adjustment.
- Fabric itself doesn't change the volume of topping material, but it's good practice under gravel and mulch to suppress weeds. A gravel driveway or patio, though, is usually built in layers — a coarse base course topped by a finer surface course — so you'd calculate each layer's depth separately and add them. For a simple decorative topping over existing soil or fabric, just use the finished depth you want; the calculator gives the volume for that single layer.
- The volume (cubic yards and cubic feet) is exact geometry. The weight uses typical material densities, which vary with moisture content, particle size, and the specific product — wet topsoil weighs noticeably more than dry, and different gravels differ. So treat the tonnage as a planning figure for delivery limits and whether you can move it yourself, not a precise number. If weight is critical (for a trailer's capacity, say), ask your supplier for the density of their specific product.
- The method is identical; only the units change. Outside North America, bulk material is sold by the cubic metre rather than the cubic yard (one cubic metre is about 1.3 cubic yards, or 35.3 cubic feet). To work in metric, compute your area in square metres, multiply by the depth in metres, and you have cubic metres to order. The same depth guidance applies — for example, 75 mm of mulch is about 3 inches. Use your supplier's per-cubic-metre pricing to finish the estimate.
Method & sources
How it computes
Volume from area × depth: cubic feet = length × width × (depth in inches ÷ 12) × (1 + waste %); cubic yards = cubic feet ÷ 27; bags = cubic feet ÷ bag size. Weight = cubic yards × an assumed bulk density (gravel 1.4, sand 1.35, topsoil 1.1, wood mulch 0.5 short tons per cubic yard) — supplier reference values that vary with moisture and product.
What this tool implements
- 1 cubic yard = 27 cubic feet; 1 cubic metre = 1.308 cubic yards = 35.31 cubic feet (NIST Handbook 44, Appendix C)
- Bulk densities are reference values, not measurements: PCA gives 1200–1750 kg/m³ (≈1.0–1.47 short tons/yd³) for normal-weight aggregate; topsoil and mulch figures are supplier conventions
- Mulch depth guidance 2–3 in for beds (Iowa State University Extension); other depths on the page are labelled as commonly quoted, to be confirmed with the supplier
Sources
- NIST Handbook 44 (2026 ed.), Appendix C, General Tables of Units of Measurement — 27 cubic feet = 1 cubic yard; 1 cubic metre = 1.308 cubic yards. https://doi.org/10.6028/NIST.HB.44-2026
- Kosmatka SH, Wilson ML. Design and Control of Concrete Mixtures. 16th ed. Skokie, IL: Portland Cement Association; 2016 (bulk density of normal-weight aggregates 1200–1750 kg/m³).
- Iowa State University Extension and Outreach. How deep should the mulch layer be around trees and shrubs? (2–3 in on heavy soils, 3–4 in on well-drained sites). https://yardandgarden.extension.iastate.edu/faq/how-deep-should-m…
What can make this go out of date
- none at runtime
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