Is there a formula to work out how much gravel is needed for a particular volume?

In message , Jon Weaver writes

This page will help:

Or there are calculators on Cormaic's pages:

Rule of thumb 1m3 = 1.5t, so 0.07m3 = 100kg

If you are buying 25kg bags, buy 5 and take 1 back if you don't use it.

They might if you buy it from a shed, those From a BM usually don't

I followed the guide on one of the web sites you mentioned and worked it out to slightly less thatn 100kgs.. As we have a "sand and aggregate" company in our local docks (which are really cheap) I ended up buying 4x40kg bags because they were onkly £2.35 per bag! (I needed some for my another area in the garden anyway).

To my surprise, to fill the 'trech' only took 1 bag (40kgs).. Looks like I might have slightly over done it on the measurements.. Still, I would rather have too much, than run out half way through the job.

Thanks for your help.

Jon

Its about 3 metric tnnes a cubic meter from memory So you need about