River Rock Calculator

River rock is sold by volume or weight, while a landscape plan usually begins with an area and an intended depth. This calculator connects those measurements. It multiplies length by width to find coverage, converts the entered depth from inches to feet, and multiplies the three dimensions to obtain cubic feet. Dividing by 27 converts cubic feet to cubic yards, the volume commonly used for bulk landscape aggregate in the United States. Weight depends on bulk density rather than solid stone density. A pile of rounded rock contains air spaces between individual pieces, so its delivered weight per cubic foot is lower than a solid block of the same mineral. A planning value near 100 pounds per cubic foot is reasonable for many dry, graded river-rock products, but supplier figures can vary with stone size, mineral composition, moisture, and compaction. The editable density field lets the estimate reflect a quarry or landscape-yard specification. Installed depth should suit both the rock size and the project. Small pebbles may cover evenly at about two inches, while larger cobbles often need three or more inches to hide fabric and create a stable appearance. Very shallow installations can expose bare spots after traffic or settlement. Measure several locations when the ground is uneven, and use an average depth only after accounting for low areas that require extra material. The calculated quantity is a geometric estimate for a level rectangular bed. Curved borders can be divided into smaller rectangles, triangles, or circles and added together. Subtract substantial features such as planters or paved pads, but minor obstructions are often best left in the total as a practical allowance. Excavation depth, edging height, and finished grade should be checked before ordering. Delivery quantities rarely match the calculated number exactly. Add an allowance for settlement, spillage, irregular boundaries, measurement error, and future touch-up. Five to ten percent is common for simple beds, while complicated shapes or uncertain subgrade may justify more. Confirm whether a supplier sells by cubic yard, short ton, or bag, and ask for the product-specific conversion. This river rock calculator provides a consistent starting point for budgeting, ordering, delivery planning, and comparing decorative aggregate options, but the supplier's scale ticket remains the final measure of delivered weight.