Stone Dust Calculator

A stone dust calculator estimates how much stone dust - the fine fraction of crushed stone, also sold as crusher dust, stone screenings, or quarry dust - a project needs, working from the area, the finished depth, an optional additive allowance for compaction and waste, and an optional stone type. It reports the finished volume and the loose order volume in cubic feet and cubic yards, an approximate count of 0.5-cubic-foot bags, and an approximate weight range in US short tons. Volume is pure geometry; weight is an approximate estimate range, because there is no single published density and it varies with the geological source, processing, and moisture (FHWA-RD-97-148).

Multiply the area in square feet by the finished depth in feet (inches divided by 12) for the finished volume in cubic feet, then divide by 27 for cubic yards. For a rectangle that is length x width x (depth in inches / 12) / 27. A compacted base over 120 square feet at a finished 4 inches is 40 cubic feet; adding a 25 percent allowance for compaction and waste gives a loose order volume of about 50 cubic feet, or 1.85 cubic yards - roughly 100 standard 0.5-cubic-foot bags and about 2.5 to 2.7 US tons.

Work in two volumes. The finished volume is the area times the depth you want after compaction: area in square feet times (depth in inches / 12) is the cubic feet. The order volume is the loose material you actually buy: finished volume times (1 + allowance percent / 100). Divide either figure by 27 to convert cubic feet to cubic yards. The calculator then turns the order volume into a 0.5-cubic-foot bag count, rounded up, and multiplies the order volume in cubic yards by an approximate loose-density estimate to get a weight range.

Use it for the compacted aggregate base beneath a paver project, not for the thin bedding layer directly under the pavers. For the base, multiply the paver area by the base depth in feet and divide by 27: a 100-square-foot patio at a 4-inch base is about 1.2 cubic yards, and a residential driveway is commonly built on about 6 inches over well-drained soils (CMHA PAV-TEC-002). For the bedding layer, follow your project specification: CMHA PAV-TEC-017 states that limestone screenings and stone dust are not recommended as bedding sand and calls for a concrete sand meeting ASTM C33 or CSA A23.1 FA1. FHWA-RD-97-148 notes screenings can be used in a granular base course when properly blended. Use the Paver Calculator for the unit count and the Gravel Calculator for a full base estimate.

Volume scales directly with depth: doubling the depth doubles the cubic feet and cubic yards for the same area. One cubic yard of stone dust covers about 324 square feet at 1 inch deep, about 108 square feet at 3 inches, and about 81 square feet at 4 inches. For a compacted aggregate base, CMHA gives common guidance of a minimum of about 4 inches for sidewalks, patios and pedestrian areas over well-drained soils, and about 6 inches for residential driveways over well-drained soils (PAV-TEC-002); go deeper on weak or poorly drained soil. A thin screeded leveling course for other uses is often only 1 to 2 inches - follow the requirements for your specific material and application.

For a layer you compact to a set depth, yes. The allowance field is additive - it adds a percentage to the finished volume - so it should be larger than the fraction the material loses when compacted, because you are working back from the finished volume. As arithmetic: if a layer loses about a fifth of its loose volume it needs about a quarter more ordered, and a one-quarter loss needs about a third more. Add roughly another 5 to 15 percent for spillage and uneven ground. A lightly screeded course compacts little, so a small allowance is enough there. The exact loose-to-compacted change depends on the material and effort - confirm it with your supplier for a large order.

No. Stone dust, crusher dust, and screenings are the fine fraction of crushed stone and contain a large share of very fine particles; bedding sand for segmental paving is a washed concrete sand. CMHA PAV-TEC-017 states that limestone screenings and stone dust are not recommended for bedding sand, which should conform to the ASTM C33 or CSA A23.1 FA1 concrete-sand gradation with a limit of about 1 percent passing the No. 200 sieve. Screenings can be used in a granular base course when properly blended and meeting the base specification (FHWA-RD-97-148). The base and the bedding sand are separate layers with separate requirements - follow your project specification.

Stone dust has no single published density. Its properties vary with the geological source of the rock, the crushing and processing method, and moisture - FHWA describes screenings as a damp, sand-sized material at roughly 5 to 10 percent moisture content (FHWA-RD-97-148). This calculator applies approximate loose-density estimates - about 2,700 to 2,900 pounds per cubic yard by default, roughly 2,600 to 2,800 for limestone or dolomite screenings and 2,800 to 3,000 for granite or trap rock - and always shows weight as a range. These are planning estimates, not published standards; confirm the unit weight with your supplier before ordering by the ton.

Order stone dust by the cubic yard or by the ton. Give the supplier the area, the finished depth, and the allowance you applied, and ask for their own unit weight if you are buying by weight, because it is the figure that determines the tonnage. Suppliers usually set a minimum bulk order and a delivery fee, so a small job can be cheaper in bags. Round the order up rather than down - running short mid-job means a second delivery.