Calculating amount of gravel, membrane and gravel stabiliser for driveway

Hi Ellie, many thanks for your question, firstly you need to work out the square meter or m2: 7 x 7 = 49m2 then the cubic meter or M3 not knowing your depth requirement of gravel but all you need do is times the 49 x the depth ie .050 for 50mm depth. Then multiply this by a conversion factor of 1.6 to give you your total weight then divide this by bulk bag weight (normally 800-900kg) to gibe you the number of bags needed. membrane = 49m2 divided by the m2 stated on the chose membrane roll. how this helps, if your stuck drop me a message and i can help clarify further.