Aggregate calculator
The volume is arithmetic and this gets it exactly right. The weight is not, and every calculator that prints one is using a density that is not a measurement of your load. Nothing you type here leaves your browser — it is worked out on your own device, so there is nothing to send and nothing to log.
This page deliberately does not know what your aggregate weighs. BS EN 1097-3 specifies a test method for loose bulk density and publishes no values, so there is no figure to fall back on and none is invented here. The volume is exact; the weight is your supplier's number, not this page's.
Why this page asks you for the density
Every other aggregate calculator multiplies your volume by a bulk density and gives you a weight to four figures. Ask where the density came from and the trail usually runs out. It is on a calculator page, which took it from another calculator page.
The standard that ought to hold it is BS EN 1097-3, Tests for mechanical and physical properties of aggregates — determination of loose bulk density and voids. It specifies the test procedure for measuring the loose bulk density of a dry aggregate. It publishes no typical values at all.
That is the standard’s considered position rather than a gap in it: the density belongs to the material in the yard, and the way to know it is to measure that material.
A correction, and it is ours
This page used to say that nobody publishes a density for aggregate. That was too strong, and it was our mistake rather than a change in the world.
A European structural design standard does publish nominal densities for aggregates, sand, gravel and cement, as ranges, for working out what a structure has to carry. It is a different kind of number from the one this page is about — a figure to design against, not a measurement of your load — but it exists, it is published, and saying otherwise was wrong.
We are not reproducing it. It is copyright, it is behind a paywall, and permission has been asked for and not yet given. Until it is, this page does what it has always done: the volume exactly, and your supplier’s figure for the weight.
Which is, in fairness, what you should be using anyway. A nominal design value describes a material named as broadly as “aggregate”. Your supplier is describing the stone in their yard this week.
How much of it is water — the one figure anybody publishes
HMRC have to weigh aggregate, because the Aggregates Levy is charged by the tonne. Their guidance allows a standard water content of
- 7% for sand
- 4% for rock
- 3.5% for gravel
Those are not densities. They are the size of the thing a single density hides. A sand that is seven per cent water by the tax authority’s own reckoning does not have one weight per cubic metre, and a figure quoted to four significant figures is offering precision the material does not have.
What to ask for
Ask your supplier what a cubic metre of the material weighs, or what is in a bulk bag and how much of a cubic metre it is. Either answer fills the box above, and the arithmetic then has your supplier’s number in it rather than somebody’s guess.
If they say “about a tonne and a half”, that is a better answer than 1,520 kg/m³ from a website, because it comes with an honest “about” attached.
The volume, at least, is certain
Length times width times depth, with the depth in millimetres because that is how a depth of chippings is specified. Nothing in that is estimated, and it is the part of the job worth getting exactly right — a patio 50 mm deep instead of 40 is a quarter more material before anybody argues about density.