River Rock Calculator
Calculate the amount of river rock you need by entering the dimensions of your landscaping area. Estimate material using dimensions, area, or volume.
Results: River Rock Needed
| tons | |
| cu yds |
Estimated Material Cost
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Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.
How to Calculate the Amount of River Rock Needed
The first step in calculating how much river rock you need for a landscaping project starts with measuring the area you plan to cover.
First, measure the length and width of the space in feet.
Then, you need to decide how deep you want the rock layer to be. Note that most landscaping projects use a depth of 2 to 4 inches. You’ll need to convert the depth to feet by dividing the inches by 12.
Next, multiply the length by the width by the depth to find the total amount of river rock needed in cubic feet.
Most landscape suppliers sell river rock in cubic yards or tons. To convert cubic feet into cubic yards, simply divide by 27, since there are 27 cubic feet in one cubic yard.
Formula: River Rock in Cubic Yards
Thus, the formula for river rock in cubic yards is:
cu yds = length(ft) × width(ft) × depth(ft) / 27
So, the amount of material needed in cubic yards is equal to the length times the width times the depth of the space in feet, divided by 27.
For example, if your landscaping bed is 12 feet long, 8 feet wide, and 3 inches deep (0.25 feet), the calculation looks like this:
(12 × 8 × 0.25) ÷ 27 = 0.89 cu yds
It’s generally a good idea to round up slightly to ensure you have enough material.
Once you know the cubic yards, you may need to convert that amount into tons, since many suppliers sell river rock by weight. The density of rock and stone varies based on its size and shape, along with its density.
River rock differs from gravel and crushed stone in both appearance and texture. River rock is naturally rounded and smooth because it has been shaped by flowing water over time.
Formula: River Rock in Tons
One cubic yard of river rock weighs roughly 1.2 tons and can vary from 1.1 to 1.4 tons, while gravel weighs roughly 1.4 to 1.7 tons. To convert, use this formula:
tons = cu yds × tons/cu yd
Therefore, the amount of material needed in tons is equal to the volume in cubic yards times the weight per cubic yard of the material.
For example, if you need 2 cubic yards and your supplier states the river rock weighs 1.2 tons per cubic yard, the calculation looks like this:
2 cu yds × 1.2 tons/cu yd = 2.4 tons