Choose the right aggregate.
Choose for the job first, then select material, grading and quantity. Rock type, particle shape, size distribution and fines all matter. A label such as “3/4-inch gravel” does not tell you whether the product is rounded, crushed, clean or mixed with fines.
Start with your project
| Project | What to compare | What to check |
|---|---|---|
| Driveway base | Well-graded angular aggregate base, such as a locally specified 3/4-inch-minus or 1½-inch-minus blend | Subgrade, layer thickness, drainage and compaction requirements. Decorative rounded stone is not a structural base. |
| Unpaved driving surface | Locally specified crushed surface aggregate with a controlled blend of sizes and fines | Traffic, dust, slope and maintenance. Clean single-sized stone behaves differently from a dense-graded road surface. |
| Garden path or patio | Fine crushed material / decomposed granite for a firmer compacted finish; small pea gravel for a loose decorative finish | Edging, tracking, slope and mobility needs. Loose gravel can be difficult for wheelchairs and strollers; verify accessibility requirements. |
| Drainage trench | Clean washed aggregate meeting the drain design; 3/4-inch / #57-type products are common candidates | Actual grading, pipe openings and filter compatibility. Fines can obstruct drainage; a stone layer still needs a suitable outlet and design. |
| Decorative planting bed | Pea gravel, river rock, crushed decorative stone or lava rock | Appearance, maintenance, containment, leaf removal and plant needs. Larger stones are harder to walk over. |
| Paver installation | Base and bedding materials required by the paver manufacturer | Do not replace specified bedding with arbitrary sand or stone. Permeable paver systems may require distinct open-graded layers. |
Material reference
The values below are editable calculator assumptions for loose bulk material, not measured supplier specifications or guaranteed density ranges. Limestone, granite and other rock sources can differ. The same material can have different density across gradings and moisture conditions.
| Material / planning density | Example sizes | Selection notes |
|---|---|---|
| Crushed stone (limestone / granite) Approx. 1.40 US tons/yd³ | 3/8-inch clean 3/4-inch clean / #57-type 1½-inch clean | Small angular stone for some paths and decorative surfaces; can move under traffic. |
| Aggregate base / crusher run Approx. 1.50 US tons/yd³ | 3/4-inch minus 1½-inch minus | Angular blend down to fines for compacted base and some unpaved surfaces; not a substitute for clean drainage stone. |
| Pea gravel Approx. 1.30 US tons/yd³ | 1/4–3/8 inch 3/8–1/2 inch | Small rounded decorative aggregate for patios and beds. Needs containment and can feel loose underfoot. |
| River rock / rounded gravel Approx. 1.35 US tons/yd³ | 3/4–1½ inches 1½–3 inches | Decorative beds and some drainage applications when washed and specified. |
| Decomposed granite / granite fines Approx. 1.30 US tons/yd³ | Fine / 1/4-inch minus | Pathway candidate when properly graded, installed and compacted. Stabilized and unstabilized products behave differently. |
| Sand Approx. 1.35 US tons/yd³ | Concrete / coarse sand Masonry / fine sand | Use the specified sand for the application; not automatically interchangeable with bedding or masonry sand. |
| Recycled concrete aggregate Approx. 1.40 US tons/yd³ | 3/4-inch minus Clean coarse | Potential compacted base where permitted. Verify grading, cleanliness and suitability for the site. |
| Lava rock Approx. 0.65 US tons/yd³ | 3/8–3/4 inch 3/4–1½ inches | Lightweight decorative mulch; porous, rough material. Supplier density varies substantially. |
| Custom / supplier-specified aggregate Approx. 1.40 US tons/yd³ | Supplier specification | Enter the supplier’s loose bulk density and use their grading specification. |
How to read stone sizes
Clean / washed: typically indicates limited fines; verify the actual grading. Minus: generally indicates a blend from the stated top size down to smaller particles and fines. Nominal size: is a product designation, not a promise that every particle has that diameter. #57, #8 and similar numbers: describe grading classifications; confirm the applicable specification and supplier sieve analysis rather than treating the number as an inch measurement.
Small stone may be easier underfoot but can track or migrate. Larger stone changes surface texture and can be difficult to walk or drive over. Mixed sizes with controlled fines can compact densely, while clean coarse aggregate leaves more open voids. These tradeoffs matter more than a decorative product name.
Material size changes the choice—not the volume formula
A 20 × 10-foot area at 3 inches deep still has the same geometric volume regardless of the stone selected. Weight changes with bulk density. Size and grading can affect density and installation needs, but there is no reliable universal size multiplier. Select the product, replace the assumed density with the supplier’s value, and confirm loose quantity versus finished compacted depth.
Four questions for the supplier
- What is the exact product grading, and is it clean or minus?
- What is its loose bulk density in US short tons per cubic yard?
- Is it suitable for this use, and what installation specification should I follow?
- How much loose material achieves my required finished depth?
Further reading
Vulcan Materials: construction aggregates · Penn State Extension: access-road material and drainage selection · Home Depot: decorative stone types
These resources describe product categories and applications; the calculator densities are separate planning assumptions. Updated October 24, 2026.