Gravel calculator
How much gravel or crushed stone to order, by volume and weight, for paths, bases and pads.
How it works
Area × depth gives the volume of stone. We add 5% for spreading and settling, then convert to bags and an approximate delivery weight.
Weight = volume × density. We start with 1.6 tonnes per m³ (about 1.35 US tons per cubic yard). Suppliers often quote about 1.35–1.4 tons per yard for clean crushed stone, and more for crusher run or road base. Change the density to your supplier's figure; wet stone weighs more.
Worked example
A 12 × 18 ft parking pad at 3 in deep: 216 sq ft × 0.25 ft = 54 cu ft, which is exactly 2 cu yd. At the default density that is about 2.7 tons, or 108 bags of 0.5 cu ft.
In the UK, an 8 m × 1 m path at 50 mm needs 0.42 m³ with 5% extra, about 0.67 tonnes: one 850 kg bulk bag.
Bags sold by weight
UK, Canadian and Australian stores often sell gravel by the kilogram. We turn weight into volume with the density, so a 20 kg bag at 1.6 t/m³ fills about 12.5 litres. If your stone is lighter or heavier, change the density and the bag count updates.
Depth guide
- Decorative gravel over membrane: about 2 in (50 mm).
- Footpaths: 2–3 in (50–75 mm) on a firm base.
- Driveways: a deeper compacted sub-base plus a top layer. Calculate each layer separately with its own depth and density.
Common questions
How many tons is a cubic yard of gravel?
Usually about 1.35 to 1.5 US tons, depending on the stone and how wet it is. Crusher run and road base sit at the heavy end.
How much does a tonne of gravel cover?
At 50 mm deep and 1.6 t/m³, one tonne covers about 12.5 m². Deeper layers cover less.
Reviewed by Alex Rowan, Editor. Last reviewed . How we calculate · Report a problem