Rip Rap Calculator

Select a rip rap type, measurement unit, and rectangular or circular area. For a rectangle, enter length, width, and depth. For a circle, enter diameter and depth. The unit selector accepts inches, feet, yards, or meters. The calculator converts dimensions to meters before calculating area and volume.

Rectangular area = length × width; circular area = π × (diameter ÷ 2)². Volume = area × depth. Estimated weight in metric tonnes = volume in cubic meters × the selected preset density in kg/m³ ÷ 1,000. Estimated material cost = metric tonnes × cost per tonne. These calculations assume a uniform depth over the entered area.

For example, select Class 1, meters, and a 10 m × 5 m rectangular area with 0.3 m depth. Leave cost per ton blank to use the preset $45 per tonne. The calculator shows 50.00 m² area, 15.00 m³ volume, 24.00 tonnes estimated weight (15 × 1,600 ÷ 1,000), and $1,080.00 estimated material cost (24 × 45). These figures follow the calculator's assumptions, not a supplier quote or verified order quantity.

The type selector changes only two stored values: density and default cost per metric tonne. Class names are calculator labels; they do not choose a stone diameter, grading specification, or design class. The density values below are tool assumptions, not verified loose bulk densities for a supplier's material. The calculator does not model the void fraction between stones or distinguish solid-stone density from delivered loose bulk density.

Confirm a loose bulk density and price for the actual material with the supplier before converting the volume to delivery weight or ordering. Recycled concrete is not a selectable preset.

The calculator accepts layer depth but does not determine an appropriate stone size, gradation, layer thickness, slope stability, or protection design. Its Class 1–4 labels do not encode those specifications. Select a design and depth from project drawings or qualified site-specific guidance before using the volume estimate.

For a sloped surface, the entered rectangle or circle represents only the dimensions supplied to the tool. It does not increase the area for slope length or calculate an irregular boundary. It also does not calculate a filter layer, toe detail, or void adjustment.

The area and volume calculation can support a preliminary quantity estimate for a planned rip rap layer, such as one on a bank, channel, shoreline, or slope. Suitability for erosion control depends on site conditions and a separately specified stone and installation design; the calculator does not assess hydraulic or structural performance.

Measure the area and specified depth for the actual installation. Account separately for slope geometry, irregular edges, filter materials, toe details, and any project allowance. The displayed volume and weight do not include these items. Confirm the material specification and delivery basis before ordering.

The cost field accepts a nonnegative price per metric tonne. Leave it blank to use the selected preset's stored default shown above; enter a supplier quote to replace that default. The displayed cost is estimated weight × entered or default price. Preset prices are calculator assumptions, not current market prices. The result does not add transport, labor, site preparation, filter materials, taxes, or other project costs.