How much gravel you need to cover 150 square foot?

Answer 1

Depends on depth of gravel you plan to put down. For each 1 inch depth:

Estimate gravel having a density of 2.7.

150 x 1/12 x 62.4 x 2.7 = 2106 pounds (slightly more than 1 ton)

so if you want 3 inches of gravel you need about 3 tons of gravel