How Much Material Do You Need?
Irregular areas
Rectangle
Measure Length and Width (in feet)
Length x Width = square feet
Determine desired depth of material (see recommended depths and chart below)
Square feet divided by sq. ft. per yard (from chart) = cubic yards needed
Example: A rectangular area 16 feet long by 10 feet wide and you want 4 inches deep of stone.
Calculations:
16 x 10 = 160 square feet
160 divided by 81 = 2 cubic yards (81 comes from the chart, 81 is how many square feet 1 cubic yard covers at a 4 inch depth)
Triangle
Measure length and width of 2 sides
Length x Width x 0.5 = square feet
Square feet divided by sq. ft. per yard (from chart) = cubic yards needed
Example: Given a triangle are where one side is 40 feet long, one side is 10 feet long and you want 4 inches deep of mulch or stone
Calculations:
40 x 10 x 0.5 = 200 square feet
200 divided by 81 = 2.5 cubic yards (81 comes from the chart)
Circle
Determine radius (1/2 distance of diameter or distance across)
Formula: Radius x Radius x 3.14 = square feet
Square feet divided by sq. ft. per yard (from chart) = cubic yards needed
Example: Given a circle 30 feet across (15 ft radius) and you want 3 inches deep
Calculations:
15 x 15 x 3.14 = 706.5 square feet
706.5 divided by 108 = 6.5 cubic yards
Conversion Chart – Square Feet to Cubic Yards
Converts square feet to cubic yards 1 cubic yard will cover the following amount of square feet at the given depth.
1/4″ deep 1296 square feet
1″ deep 324 square feet
2″ deep 162 square feet
3″ deep 108 square feet
4″ deep 81 square feet
6″ deep 54 square feet
12″ deep 27 square feet
Recommended Depth of Materials
Bark Mulches 3″
Stone less than 1″ diameter 3″
1-1 1/2″ Riverstone 4″
Soil for Lush Lawns 4+”
Garden Soil in Flower Beds 6-12″
Lawn topdressing 1/4″
Pathways 4″
