Calculator 03 / 08
Crushed stone calculator
For crushed stone and aggregate — #57, #2, crusher run — where the stone is often compacted and usually sold by the ton.
- Outputs
- yd³ · tons · tonnes · bags · cost
- Material basis
- Crushed stone · 105 lb/ft³ default, editable
- Method
- Formulas & sources
When crushed stone is the right material
Crushed stone is broken rock with angular faces. The angles lock together under load, which is why it is used for shed pads, patio and paver bases, and driveway layers, rather than smooth pea gravel or river rock. It is normally sold by the ton, so the tons figure here matters more than on a decorative job.
Size numbers such as #57 (1 in down to about 3/16 in) and #2 (2½ in to 1½ in) describe the grading ASTM D448 summary. See types and sizes for what each is used for.
Compaction allowance
Loose stone packs down when you compact it with a plate compactor or when it's driven on. If the depth you measured is the finished, compacted depth, you need to order more loose stone than the plain volume. A gravel-roads manual written for the Federal Highway Administration notes that compaction from placement, moisture and traffic “will result in 30% or greater reduction in volume” in many areas source. A 30% reduction means ordering about 43% more loose material (1 ÷ 0.7). The calculator starts at 0% — set the allowance to match how the stone will be compacted, and check with your supplier.
Worked example: shed pad
| Pad | 16 ft × 12 ft = 192 ft², 4 in deep |
|---|---|
| Volume | 64 ft³ = 2.37 yd³ |
| + Waste 10% | 70.4 ft³ = 2.61 yd³ |
| Weight at 105 lb/ft³ | 7,392 lb ≈ 3.70 US tons |
With a 20% compaction allowance as well, the purchase volume becomes 64 × 1.20 × 1.10 = 84.5 ft³ (3.13 yd³). The two allowances multiply; they aren't simply added.
Reading the result
Each line of the order sheet answers a different question. Read them in order: geometry first, then your allowances, then the quantity you can actually buy.
- Calculated volume
- Area × depth — pure geometry, before any allowance.
- + Compaction
- Extra loose material if the depth is a compacted depth. Shown only when set.
- + Waste
- Your margin for spillage, edges and uneven ground, applied after compaction.
- Purchase volume
- What to buy: volume × (1 + compaction) × (1 + waste). The exact figure.
- Estimated weight
- Purchase volume × the density shown. Only as accurate as that density.
- Bulk order
- Purchase volume and weight rounded up to the next ½ yd³ / ½ ton (½ m³ / ½ t in metric).
- Bags / cost
- Whole bags of the size you entered; cost = your price × the matching quantity.
What this calculator assumes
- Dimensions are the plan area that will actually be covered.
- Depth is an average across the area.
- Areas are flat; slopes aren't adjusted for.
- Density is a loose bulk density — a general published value unless you replace it.
- Waste and compaction are multiplied, not added.
- Bags are rounded up to whole bags; bulk orders up to the next ½ unit.
- Uses the general dry-gravel value. Crushed products vary with rock type and grading; supplier figures are more accurate.
It can't see your site or your supplier's stone. What the calculators cannot know · Full methodology
Common mistakes with this calculator
Forgetting compaction on compacted layers
What goes wrong: Stone packs down. A 30% volume reduction needs about 43% more loose material than the geometric volume.
How to avoid it: If your depth is the finished, compacted depth, set a compaction allowance. Leave it at 0 for loose decorative cover.
Treating tons and cubic yards as the same thing
What goes wrong: Weight depends on the material. The same 2 yd³ is about 2.62 tons of dry sand but 3.38 tons of wet gravel at the reference values.
How to avoid it: Convert with a density you can see — ideally your supplier's — using the yards-to-tons calculator.
Assuming every gravel weighs the same
What goes wrong: The published gravel range of 91–120 lb/ft³ turns 2 yd³ into anything from 2.46 to 3.24 tons.
How to avoid it: Ask the supplier for their weight per yard or conversion factor and type it into Density.
Questions
How much does a cubic yard of crushed stone weigh?
It varies with rock type, size and moisture. We use 105 lb/ft³ (about 1.42 US tons per yd³) as a general default, within a published gravel range of about 1.23–1.62 tons per yd³. For crushed stone, ask the quarry or supplier for their conversion factor and enter it.
Do I need to allow for compaction?
If the depth you want is the compacted depth, yes. Set the compaction allowance to the extra loose material you expect to need. The calculator shows it as its own line.
What is an aggregate calculator?
It's the same calculation: area × depth for volume, then volume × density for weight. Choose the material closest to your aggregate and replace the density with the supplier's value.