Free online tool • Screenings & fines
Stone Dust Calculator
This stone dust calculator works out how much stone dust — also sold as screenings or crusher fines — a paver bed, flagstone patio, path or pool base needs. Enter the area and the finished compacted depth, and it adds the extra loose material lost to compaction before giving tons, cubic yards, bags and cost.
How Much Stone Dust Do I Need?
What Is Stone Dust?
Stone dust is the fine material left over when a quarry crushes and screens rock — particles from about 3/16 inch down to powder. It goes by several names depending on the region and the rock: screenings, crusher fines, rock dust, limestone screenings or granite fines. Because the grains are angular and graded, stone dust packs into a firm, flat layer under a plate compactor, which is why it is used as a setting bed for pavers and flagstone and as a surface for paths.
How the Stone Dust Calculator Works
1. Area
Multiply length by width in feet. A 12 × 16 ft patio is 192 sq ft.
2. Compacted volume
Multiply by the finished depth in inches divided by 12, then divide by 27. A 1 inch bedding layer: 192 × 0.083 ÷ 27 = 0.59 cubic yards.
3. Add compaction
Stone dust is delivered loose and loses about a quarter of its volume when compacted, so multiply by 1.25: 0.59 × 1.25 = 0.74 loose cubic yards.
4. Tons and bags
Multiply by the density of about 1.45 tons per cubic yard: 0.74 × 1.45 = 1.07 tons, or about 43 bags of 50 lb.
Stone Dust Weight and Compaction
| Material | Loose tons per cubic yard | Typical compaction factor |
|---|---|---|
| Stone dust (blend) | 1.45 | 20–30% |
| Limestone screenings | 1.45 | 20–30% |
| Granite screenings | 1.50 | 20–25% |
| Decomposed granite | 1.45 | 10–20% |
Once compacted, stone dust weighs about 1.7 to 1.8 tons per cubic yard. Wet stone dust is heavier still, so a load bought by the ton after rain covers a little less. The gravel compaction calculator explains compaction factors for coarser base materials.
How Deep Should Stone Dust Be?
- Paver bedding: 1 inch, screeded flat over a compacted gravel base. Do not go thicker; deep bedding lets pavers rock and rut.
- Flagstone setting bed: 1 to 2 inches, deeper for irregular stone so each piece can be bedded level.
- Path or walkway: 2 to 3 inches over 3 to 4 inches of crushed stone base.
- Above-ground pool base: about 2 inches, levelled and compacted inside the pool ring.
- Horse stall or arena: 3 to 4 inches, compacted in layers.
The stone dust layer always sits on a stronger base. Use the paver base calculator or the gravel base calculator for the layer underneath.
Stone Dust vs Sand Under Pavers
Stone dust compacts harder than sand and is often cheaper, which is why many installers use it. Its drawback is drainage: the fines hold water, and in freeze-thaw climates a saturated stone dust bed can heave. The Interlocking Concrete Pavement Institute specifies coarse concrete sand (ASTM C33) for bedding. For a patio in a wet or cold climate, sand is the safer choice; for a dry, well-drained site, stone dust works well. The sand and gravel calculator handles a sand bedding layer.
Stone Dust Bags vs Bulk
A 50 lb bag of stone dust holds a little under half a cubic foot, so one ton is 40 bags and covers roughly 180 sq ft at 1 inch compacted. Bagged stone dust costs $5 to $8 per bag; bulk stone dust costs $25 to $45 per ton at the quarry plus delivery. Above about half a ton, bulk is far cheaper.
Related Stone Calculators
Plan the layers above and below the stone dust:
- Stone calculator — every stone type in tons and yards
- Paver base calculator — gravel base, bedding and pavers together
- Crusher run calculator — the compacted base under a path or patio
- Gravel compaction calculator — loose vs compacted volume
- Limestone calculator — limestone screenings and crushed limestone
Bedding guidance follows the Interlocking Concrete Pavement Institute recommendation of ASTM C33 sand; stone dust densities follow typical quarry ranges for screenings.
Stone Dust FAQ
How much stone dust do I need for 100 square feet?
About 0.56 tons at 1 inch compacted depth, 1.1 tons at 2 inches and 1.7 tons at 3 inches, including a 25 percent compaction allowance. That is roughly 23, 45 and 68 bags of 50 lb.
How much does a yard of stone dust weigh?
Loose stone dust weighs about 1.45 tons, or 2,900 lbs, per cubic yard. Compacted it reaches about 1.7 to 1.8 tons per cubic yard, and wet stone dust weighs more.
How many bags of stone dust are in a ton?
40 bags of 50 lb or 50 bags of 40 lb. One cubic yard of loose stone dust is about 58 bags of 50 lb.
How thick should stone dust be under pavers?
1 inch, screeded level over a compacted gravel base. A thicker bedding layer lets pavers settle unevenly. Use 1 to 2 inches for irregular flagstone.
Does stone dust compact?
Yes. Stone dust loses about 20 to 30 percent of its loose volume under a plate compactor, which is why the calculator adds a 25 percent compaction factor by default. Lightly dampen it before compacting for the firmest result.
Is stone dust the same as screenings?
Yes. Stone dust, screenings, crusher fines and rock dust all describe the fine material left after crushing rock. Limestone screenings and granite screenings are the same product from a specific rock.