Two things missing from the question: The depth and the type of gravel. But here is an example for you: 365 sq ft at 4 inches deep and using # 11 stone ( pea gravel ). It generaly takes 1 1/2 ton per CUBIC YARD of crushed stone, so first lets figure the cubic feet: 4/12 = 0.33 x 365 = 120 cu ft divided by 27 cu ft in a cu yd = about 4 1/2 yard divided by 1.5 ton = about 3 tons of stone ( these figures are rounded to the nearest on the calculator and not exact) Always order a little extra stone because it will settle some over time.