Gravel is bought in cubic quantities, or by weight.
You ask "to fill" but you only give a square measure. The volume of gravel required wil depends on the depth you wish the gravel to be.
To fill 81 square metres to a depth of 5 cm would require 4.05 cubic metres of material.
500 m2 = 775,001.55 inches squared.
it depends how thickly you lay it.
about 71 cubic metres of gravel i think
16 cubic yards
To determine how much gravel is needed to fill an area of 10 by 5 feet, you first calculate the area by multiplying the length and width: 10 feet × 5 feet = 50 square feet. Next, decide on the desired depth of the gravel fill (for example, 3 inches or 0.25 feet). Multiply the area by the depth to find the volume in cubic feet: 50 square feet × 0.25 feet = 12.5 cubic feet of gravel required.
100 meters squared
500 m2 = 775,001.55 inches squared.
unit of area
it depends how thickly you lay it.
about 71 cubic metres of gravel i think
2.438 2.438
17.65 meters squared
4,219.5 square feet.
Four square meters is 43.1 square feet.
16 cubic yards
471 (square meters) = 5,069.80181 square feet.
85002 is 8500 x 8500 which is: 72250000