Math CentralQuandaries & Queries


Question from Maggie:

I am wanting to know how many tons of dirt we r going to need to fill a basement.
The measurements we r going with r 15ftx15ftx8ft.

Hi Maggie,

Finding the volume of dirt needed in cubic feet is easy if you use our volume calculator. The weight however is more challenging. The difficulty is that not all dirt is the same. The NIST Handbook called Specifications and Tolerances for Field Standard Weight Carts gives the density of dirt as 120 lbs per cubic foot but the SIMetric site in the UK has various types of dirt with densities. The densities are given in kilograms per cubic metre but Google can convert to pounds per cubic foot.

My suggestion is that you look at the SIMetric site, scroll down to "Earth" and decide which description best fits your situation. For illustration I took "Earth, moist, excavated" which has a density of 1442 kilograms per cubic metre. To convert this to pounds per cubic foot I typed 1442 kilograms per cubic metre in pounds per cubic foot into Google and got the response (1442 kilograms) per (cubic meter) = 90.0211192 pounds per (cubic foot). You could then multiply 90 pounds per cubic foot by the volume in cubic feet you obtained from our volume calculator to find the weight in pounds. There are 2,000 pounds in a ton so dividing the weight in pounds by 2,000 will yield the weight in tons.

I hope this helps,

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