How much gravel you need depends on area, depth, and the material's density — not a flat number per stone type. This calculator turns your own dimensions into a cubic-yard (or cubic-metre) figure and a weight in tons or tonnes you can take straight to a supplier.
A 20 ft × 10 ft path at 4 inches deep is 2.59 cubic yards
Multiply length by width by depth for raw volume, then convert: length × width × (depth ÷ 12) ÷ 27 turns feet and inches into cubic yards, and length × width × (depth ÷ 100) turns metres and centimetres into cubic metres. Weight is that volume multiplied by the material density, and the Units field switches the whole calculation between cubic yards and tons and cubic metres and tonnes, so the conversion never lands on you.
The path in the heading is 66.7 cu ft, or 2.47 cu yd before waste and 2.59 cu yd after the 5% default waste factor; at the default crushed-stone density of 1.4 tons/yd³ that is about 3.63 tons to order. The 5% covers ordinary compaction and an uneven sub-base, and you should raise it toward 10% for a compacted base layer. Uniform depth across the area is the one geometric assumption the tool cannot relax: for an irregular or curved shape, break it into rectangles and add the volumes, or use your longest dimensions and expect a small over-estimate.
One ton covers 108 sq ft at 2 inches and 54 sq ft at 4
At the default crushed-stone density of 1.4 tons/yd³, one ton covers roughly 108 sq ft at 2 inches deep, 72 sq ft at 3 inches, or 54 sq ft at 4 inches. Read that row backwards when you already know the area: a 720 sq ft driveway at 3 inches is ten tons. Lighter or heavier material, pea gravel or crusher run, covers a different area per ton, which is exactly why this calculator works from the density you select rather than one fixed coverage number.
Round the cubic-yard or cubic-metre figure up to whatever increment your supplier delivers in: most yards quote in whole or half units, and rounding down risks a second delivery for the last few square feet. The metric arithmetic runs the same way. A 6 m × 3 m driveway strip at 10 cm deep is 1.8 m³ before waste and 1.89 m³ after the same 5%, or about 3.14 tonnes at the default 20mm-gravel density of 1.66 t/m³.
Two yards can quote the same 3/4 in stone 20% apart
Crushed stone and gravel (#57, 3/4 in, ~20mm) defaults to 1.4 US tons per cubic yard (≈1.66 tonnes per cubic metre), per LandCare Stone. Pea gravel defaults to 1.35 tons/yd³ (≈1.60 t/m³) and crusher run or road base to 1.23 tons/yd³ (≈1.46 t/m³), both drawn from landscape-supply figures. Material density is a genuinely disputed number, though: real supplier quotes for what is nominally the same product can differ by 10-20%, and wet material can weigh 5-10% more than dry. A 20% gap in density is a 20% gap in the tonnage you order, which makes it one question worth asking before the truck is booked.
That is why the density field is editable rather than fixed. Type the figure your supplier gives you into it and the volume and weight update together. What this cannot do on its own is know their exact product, or how wet it was when the truck was loaded. The naming is regional rather than technical: #57, 3/4 inch, 20mm gravel and 20mm shingle are all the same size class of roughly 3/4 to 1 inch graded angular stone, and the default Crushed stone / gravel option covers every one of those names. Its metric default of ≈1.66 t/m³ is cross-checked against a UK supplier’s own figure of ~1.7 tonnes per cubic metre.
A driveway is two calculations, not one
A typical residential driveway uses a 4-6 inch base layer plus a 2-3 inch top layer of finish stone, so 6-9 inches in total and 8-12 inches under heavy vehicles. Run the calculator once per layer with its own depth, because a compactable base course and a decorative top layer are usually different, differently-priced material: pick Crusher run / road base for the base and its denser default figure, then your finish stone for the top, and add the two results. A single pass at the combined depth does not account for that split, and it silently prices the whole build at one material. The same two-layer logic applies to the compacted base under a paver patio.
Angular stone in the drain, pea gravel in the bed, crusher run underneath
French drains typically use 6-12 inches of depth filled with angular crushed stone along the trench length, not rounded pea gravel, which packs too tightly and restricts water flow. Enter the trench length as the length, the trench width, and your fill depth to get the volume. Pea gravel earns its place in paths and beds instead: select it from the Material dropdown and the density drops to 1.35 tons per cubic yard, about 2,700 lb, lighter than angular crushed stone of the same volume. Because it is rounder and settles differently, lean toward the higher end of the waste factor range for those jobs.
Crusher run and road base sit at the third corner: at 1.23 tons/yd³ they are the lightest per cubic yard of the three defaults, but they compact hardest, which is why they belong under a surface rather than on it.
Under half a cubic yard, bagged gravel beats a delivery
A typical 0.5 cubic foot bag covers about 2 sq ft at 3 inches deep, and for small jobs under roughly half a cubic yard bagged material is often cheaper and easier than arranging bulk delivery; the calculator flags that in a warning once your result drops below that threshold. Above it, bulk gravel and crushed stone are usually sold by weight, in tons or tonnes, while some suppliers quote by volume. You get both figures from the same inputs, so you can answer with whichever one the yard asks for, and match their product with the density field if it differs from the default. Delivery minimums, bulk-bag sizes, and per-ton or per-tonne pricing all vary by supplier and region, so this tool cannot quote a price in dollars: it estimates quantity, not cost.