You will need 0.12 cubic yards of gravel for an 8x8x90' area.
1
8
You will need 20 cubic yards or 25.7 tons of gravel.
You will need 65.93 cubic yards or 84.6 tons of gravel.
Approximately 24.7 cubic yards or 31.7 tons of gravel.
260
You'll need about 28.704 cubic yards (37 tons) of gravel.
You will need about 65.185 cubic yards (83.6 tons) of gravel for this area.
Plan on about 2.2 cubic yards (2.8 tons) of gravel.
You will need about 463 cubic yards (around 594 tons) of gravel for this area.
To cover 300 square feet 4 inches thick, you would need approximately 3 cubic yards of gravel.