You will need about 463 cubic yards (around 594 tons) of gravel for this area.
2800 feet of gravel
You would need approximately 2.5 cubic yards of gravel to cover a 12' by 15' area at a depth of 2 inches.
It depends how deep you want the gravel to cover, if you want it to be 2 inches deep it's going to cost more than 5 inches. Also it depends how big the gravel is cut, I think that the smaller the gravel is the more it costs.
Based on sand and gravel calculator found on L.R. Faulk Construction Co. site, 1 ton of gravel (clean rock) will equal approximately 7.3 sq. ft x 6 inches deep, or 5.2 sq. ft x 3 inches deep. A ton of gravel will cover approximately 15 square yards (135 square feet) at 3 inches deep.
It depends how deep you go. If you do 2 inches deep the area will require at least 0.7 cubic yards (about 1,710 pounds) of gravel.
13 1/4
You'll need about 28.704 cubic yards (37 tons) of gravel.
Plan on about 2.2 cubic yards (2.8 tons) of gravel.
1 (cubic yard) = 46 656 cubic inchesIf the depth is 2 inches then the area it will cover is 46656/2 square inches = 23,328 square inches. Convert 23,328 square inches to square yards23 328 (square inches) = 18 square yards
Depends on what depth you want to spread the gravel at. This answer depends on knowing the cubic capacity of 50 lbs. of gravel.
Its really hard to guage, as it wont be at 2" everywhere. Anyway a ton should do between 15 - 18 square mts.