# How to Calculate a Stone Retaining Wall

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Tip

Purchase up to an additional 10% of material to ensure that you have enough. There are roughly 15 cubic feet in one ton.

Some regard stone retaining walls as the nicest and most natural looking types of landscaping walls. There are three types of popular stone walls: rubble (smaller stones), cut stone (stone bricks) and boulder walls (larger stones). It is harder to calculate the area of rubble and boulder walls due to the different shapes and sizes of the stones. A cut stone wall uses rectangular stones that are all of similar size. To determine the amount of stone needed to build a wall, calculate the total weight of the wall in tons.

Determine the average length, width and height of the stone in feet. Use a measuring tape to determine these values. If the area is longer than the measuring tape, use a string to take the measurement and measure the string.

Multiply the length, width and height of the wall to determine its cubic feet. For example:

20 feet by 2 feet by 2 feet = 80 cubic feet.

Divide the total cubic feet by 15 to determine the amount of stone needed in tons:

80 cubic feet / 15 = 5.334 tons of stone.

Contact a stone reseller to determine the weight of each stone. Divide the total amount of tons by the weight of each stone to determine how many stones you need. Convert the weight of each stone into tonnage before dividing:

50 pounds / 1 ton (2,000 pounds) = .025 tons 5.334 tons / .025 tons = roughly 214 stones