We normally do just the earthwork but I've been asked to bid some rock, here's the formula I have, what do tou experts think? Sq Ft divded by 160 X inch thickness = Tons compacted in place
I normally just do my cubic yards X 1.5 and add 5 - 8 % for compaction depending on what size rock. jr
Sold by the ton, I always wondered why change to inches and tons for AB & AC. Here's another formula my paving friend gave me. 12.5 lbs per sq ft per 1"thick compacted
Just to add my $.02, you will want to add a waste factor in addition to the compaction factor, as your sub-base won't be 100% uniform. Over a small area no big deal, over a large area it can add a lot to the tonnage. ( I like to use 10-15% total waste and compaction factor depending on jobsite, material used, weather conditions, etc) Vulcan Materials has a handy calculator to check your numbers that I use to check my numbers.
145436 sq ft. and 4300 tons, figuring $0.20 per sq ft. to place, compact and finish