Math CentralQuandaries & Queries


Question from Jennifer, a parent:

How many tons of sand is needed to cover 350 cubic square feet?

Hi Jennifer,

I assume you have an area of 350 square feet and you want to cover it with sand. First you need to decide on the thickness of sand you want, and you need to specify the thickness in feet. If you have the thickness in inches then divide by 12 to express it in feet. Next multiply the area (350 square feet) by the thickness in feet to find the volume of sand you need in cubic feet.

Next you need to determine how much a cubic foot of sand costs, this is the density of the sand. Unfortunately this is not straightforward to determine. Wikipedia says:

The density of a solid material can be ambiguous, depending on exactly how it is defined, and this may cause confusion in measurement. A common example is sand: if gently filled into a container, the density will be small; when the same sand is compacted into the same container, it will occupy less volume and consequently carry a greater density. This is because "sand" contains a lot of air space in between individual grains, this overall density is called the bulk density, which differs significantly from the density of an individual grain of sand.

Once you have calculated the volume I suggest you contact the supplier of the sand to ask what the weight will be.

I hope this helps,

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