Gravel Calculator

The gravel calculator finds the volume, weight, and 50-pound bag count needed for a layer of gravel, crushed stone, river rock, or another aggregate, based on the project area, the fill depth, and the material's density. Four area shapes, rectangular, circular, triangular, and trapezoidal, cover both standard and irregular layouts.

• Area shape and dimensions. A rectangular area takes length and width; a circular area takes a radius; a triangular area takes a base and height; a trapezoidal area takes two base lengths and a height. Length units run to feet, inches, yards, meters, and centimeters.
• Depth. A minimum of 2 to 4 inches is recommended for most applications; deeper fills such as playground surfacing or a driveway base call for more, as noted under Use Cases below.
• Gravel type. A preset density applies for pea gravel, crushed stone, river rock, limestone, decomposed granite, sand, lava rock, and white marble chips, since these materials pack to different weights per volume. A custom density value replaces the preset when a specific material's density is known.
• Price per unit. Optional; priced per US ton or per cubic yard, whichever matches how a supplier quotes.
• Accepted formats. Decimals (0.75), fractions (3/4), and mixed numbers (5 1/2) are all accepted, along with commas and common symbols in numeric fields.

Area follows standard geometry for the selected shape: length times width for a rectangle, pi times radius squared for a circle, one-half base times height for a triangle, and one-half the sum of the two bases times height for a trapezoid. Volume equals area times depth. Weight equals volume times the material's density. Bag count divides weight by 50 pounds, the standard bag size used for the count. Results report volume in cubic yards and cubic meters, weight in US tons and kilograms, and the bag count. Settings holds a custom density value, decimal-place precision, and a step-by-step formula display.

A rectangular area 10 feet by 20 feet, filled 4 inches (0.33 feet) deep, has a volume of 10 times 20 times 0.33, or about 67 cubic feet. Divided by 27 cubic feet per cubic yard, that is close to 2.5 cubic yards of gravel before weight or bag count are figured from the material's density.

Accurate gravel estimates prevent costly over-ordering and project delays from under-ordering across residential, commercial, and agricultural settings.

• Driveway Construction: Crushed stone or pea gravel for a residential driveway base typically runs 4 to 6 inches deep for a durable base layer.
• Patio and Walkway Base: A stable base layer under pavers, flagstone, or concrete patios uses the rectangular or trapezoidal shape for irregular patio layouts.
• Landscaping and Garden Borders: River rock or white marble chips size out for garden paths, flower bed borders, and rock gardens from the area dimensions alone.
• Drainage Projects: Gravel fill for French drains, dry wells, and drainage trenches around foundations follows directly from the trench dimensions.
• Playground Surfaces: Pea gravel for a playground area typically needs 6 to 9 inches of depth for safety compliance.
• Commercial Construction: Aggregate quantities for road base, parking lot sub-base, and building foundation preparation compare across gravel types using the price estimation feature.
• Agricultural Applications: Farm roads, livestock pen surfaces, and equipment pad areas use the circular shape for round pens and the trapezoidal shape for irregularly shaped access roads.
• Budget Planning: A price per ton or per cubic yard from local suppliers, compared across gravel types, finds the most economical option before committing to a purchase.