gizmobench

Gravel Calculator

Type an area, a rectangle or a circle, and the depth of stone you are laying, in feet and inches or in metres and centimetres, and read the volume in cubic yards, cubic metres and cubic feet at once. The density it weighs that volume at is a field on the page, not a constant behind it: it opens at 1.5 tonnes per cubic metre for loose gravel, with pea gravel and crushed stone one click away and your supplier's own figure typed straight over the top. From there come the tonnes, the US short tons and the whole bags, 40 kg and 50 lb, always rounded up. Switching between imperial and metric converts what you already typed, and nothing is rounded until the last step.

20 ft10 ft2 in
20 ft by 10 ft at 2 in1.42 t1.23 cu yd · 0.94 m³ · 33.33 cu ft1.56 US tons at 1.50 t/m³ · 36 bags of 40 kg or 63 of 50 lb
Shape
Length
Width
Depth
Material
Density t/m³
Units

The density is the figure everything after the volume depends on, so it is a field and not a hidden constant. Loose gravel is about 1.5 tonnes per cubic metre, pea gravel a little heavier, and wet stone heavier again: if your yard quotes a weight per cubic yard, divide it by 0.765 to get tonnes per cubic metre and type it in. Switching between imperial and metric rewrites what you already typed into the other system, to four decimals, rather than clearing it, and the volume is then worked from the figures on the screen.

Optional. Nothing is stored, and no rate is suggested: prices are local and they move.
  • A small border12 ft by 3 ft at 2 in
    0.22 cu yd, 0.25 t
  • A driveway30 ft by 10 ft at 4 in
    3.70 cu yd, 4.25 t
  • A circular bed8 ft across at 3 in
    0.47 cu yd, 0.53 t
Exact about the volume, honest about the weight. Length by width by depth, converted between feet, yards, metres and inches without rounding until the last step, so the volume is exact. It cannot know your supplier's density or how far the stone settles once it is walked on, so the tonnage and the bag count are estimates from a density you can change. There is no price list, no supplier and no delivery charge here, because a rate is the one input that would go stale; type your own above and the page multiplies it. Depth is a measurement you enter and this page reads back to you: what goes under a surface that carries weight is groundworks, and it is not something a quantity calculator should decide.

Common questions

How deep should gravel be for a path or a driveway?
The depths people commonly lay are about 2 inches, or 50 mm, of stone on a garden path or a decorative border, and 3 to 4 inches, 75 to 100 mm, on the top layer of a driveway. The range moves with the size of the stone, since a layer thinner than roughly twice the largest stone rolls rather than locking together, and with how much traffic the surface takes. This page does not pick the depth for you: it takes the one you have decided on and gives the quantity. The example it starts from is a path 20 feet by 10 feet at 2 inches, which is 1.23 cubic yards and 1.42 tonnes at 1.5 t per cubic metre, and the Driveway chip on the stage switches to 30 feet by 10 feet at 4 inches, which is 3.70 cubic yards and 4.25 tonnes. In metric that same chip opens 9 metres by 3 at 10 cm, which is 3.53 cubic yards and 4.05 tonnes: round metric numbers for the same kind of drive rather than a conversion of the imperial ones, so it is the slightly smaller job of the two. What goes underneath a surface that carries vehicles is groundworks and belongs with whoever specifies the job, so nothing here proposes it.
How much does a cubic yard of gravel weigh?
At 1.5 tonnes per cubic metre, the figure this page opens with for loose gravel, a cubic yard weighs 1.15 tonnes, which is 1.26 US short tons or about 2,530 lb. Switch the material to crushed stone at 1.6 and the same yard reads 1.22 tonnes; pick pea gravel at 1.7 and it reads 1.30 tonnes, 1.43 US tons or about 2,865 lb. The number moves because the gaps between the stones are a large share of the volume, and whether those gaps hold air, fine grit or water depends on the grade, the screening and the weather. That is exactly why the density sits on the page as a field you can type in.
How much area does a ton of gravel cover?
At 1.5 tonnes per cubic metre, one tonne spread 2 inches deep covers about 141 square feet, 3 inches deep about 94, and 4 inches deep about 71. A US short ton is 0.907 of a tonne, so the same three depths give roughly 128, 85 and 64 square feet. You can check any of them here: 10 feet by 10 feet at 2 inches reads 0.71 tonnes, which is one tonne over about 140 square feet. Heavier stone covers less ground per ton, so switching the material changes the answer: at pea gravel's 1.7 the same tonne covers about 125 square feet at 2 inches.
Should I order gravel by weight or by volume?
In whichever unit your supplier sells, and the page gives you both so you can check one against the other before you commit. Bulk stone is usually quoted in tons or cubic yards in the United States, in tonnes or bulk bags in the UK and Europe, and by the bag when it is bagged. The conversion between the two is the density, which is why a price per ton and a price per cubic yard are not comparable until you know what a yard weighs. If your yard names a density, or a weight per cubic yard you can work back from, type it into the density field: theirs is the number that will be on the ticket.
How many bags of gravel make a ton?
Twenty-five 40 kg bags make a metric tonne, and forty 50 lb bags make a US short ton, since 50 lb times 40 is exactly 2,000 lb. The page prints both counts for the volume you entered and always rounds up, because half a bag is not something a shop sells. The 30 by 10 foot driveway at 4 inches deep works out at 4.25 tonnes, which is 107 bags of 40 kg or 188 bags of 50 lb: past a certain point the bags stop being cheaper than a delivered load, and seeing the count is usually what settles it.
Where does the density come from, and can I change it?
It is a field, and it starts at 1.5 tonnes per cubic metre for loose gravel, with buttons beside it for pea gravel at 1.7 and crushed stone at 1.6. Those are common published figures for dry, loose aggregate rather than measurements of the stone in your yard: a wet load is heavier, a well graded one packs tighter, and a supplier's own figure beats both. Type theirs in and every number below it follows, including the three worked examples. The reason the field exists is that a tonnage handed back from a density the page never names is a number you cannot check.
Is anything uploaded, and does it cost anything?
No. The arithmetic runs in your browser, there is no account, and nothing is sent anywhere. Your measurements, the shape, the units, the job, the material and the density are kept in your browser's own storage so the page opens where you left it, and clearing your browser data clears that too. The rate field is the one thing that is never saved. There is no price list here and no supplier: a rate per tonne is set locally and moves, so the page multiplies the one you type and suggests none of its own.

Length by width by depth, converted between feet, yards, metres and inches without rounding until the last step, so the volume is exact. It cannot know your supplier's density or how far the stone settles once it is walked on, so the tonnage and the bag count are estimates from a density you can change.