From measurements to an order
How much rock will cover your space?
Not sure which material fits? Use the rock selection helper. Start with volume. Area and finished depth tell you the cubic yards; the selected rock's loose bulk density converts that volume to an estimated weight. One cubic yard covers 108 square feet at 3 inches before extra material.
Need a worked measurement example? Read how much rock to order. For a simpler single-bed tool, use the rock calculator; compare project-specific layer depths in the depth guide.
A 10 × 10 foot bed, 3 inches deep
What the default pea gravel estimate means
The measured bed needs 25 cubic feet, or 0.93 cubic yard. With the calculator's selected 10% extra allowance, plan for 1.02 cubic yards, about 1.38 short tons, or 55 bags of 0.5 cubic foot. The tonnage uses the current pea gravel planning factor of 1.35 tons per cubic yard. Confirm the supplier's actual density and bag yield before ordering.
Try your own measurements →
The calculation
Turn square feet and inches into yards, tons, and bags
The divisor combines 12 inches per foot with 27 cubic feet per cubic yard. For a circle or ring, the calculator finds its area first.
Loose bulk density varies by material, gradation, packing, and moisture. Use the supplier's value when available.
Round up to whole bags. The tool assumes each bag contains 0.5 cubic foot; check the volume printed on the product you buy.
The calculator applies your extra material allowance after finding the finished layer volume. It changes order volume, tons, and bag count together. A density change affects weight, while the same volume still needs the same number of volume-labeled bags.
Choose the material
Rock weight and coverage by material
These are the same planning factors used by the calculator above. Coverage per ton is geometric and excludes its extra material allowance. A dash means the stated depth is thinner than this tool's minimum suggested layer for that stone size.
| Rock | Typical size | Tons/yd³ | Sq ft/ton at 2 in | Sq ft/ton at 3 in |
|---|---|---|---|---|
| Pea Gravel | 3/8" | 1.35 | 120 | 80 |
| River Rock (1-3") | 1-3" | 1.325 | — | 82 |
| Crushed Limestone | 3/4" | 1.35 | 120 | 80 |
| Crushed Granite | 3/4" | 1.4 | 116 | 77 |
| Decomposed Granite | 1/4" minus | 1.25 | 130 | 86 |
| Lava Rock | 3/4-2" | 0.75 | 216 | 144 |
| White Marble Chips | 1/2-1" | 1.35 | 120 | 80 |
| River Rock (3-5") | 3-5" | 1.25 | — | — |
| Quarry Process (QP) | 3/4" minus | 1.35 | — | — |
| Riprap / Armor Stone (Example) | Per project spec | 1.4 | — | — |
| Egg Rock (1-3") | 1-3" | 1.4 | — | 77 |
| #57 Clean Stone / Drain Rock | 1/2-1" | 1.35 | — | 80 |
| Crusher Run / 21-A Base | 3/4" minus | 1.45 | — | — |
| Road Base Gravel (21-A) | 3/4" minus | 1.45 | — | — |
Swipe or scroll sideways to see every column. If your supplier gives a loose bulk density in pounds per cubic yard, enter it under Advanced Density and Compaction for a more useful ton estimate. The riprap row is only a 12-inch planning example; use the riprap calculator with the project's actual stone and thickness specification.
Match depth to the job
Calculate each layer for its actual purpose
A decorative top layer, compacted driveway base, and drainage trench solve different problems. Enter the finished depth of one layer, then run another calculation if the project also has a base.
Garden beds
Start around 2–3 inches for small decorative stone, then adjust for particle size and the look you want. Rock can collect airborne weed seeds and warm the soil; it does not make a planting bed maintenance free.
Explore landscape rock →Walkways
For a walkable surface, distinguish the visible stone from any prepared base. Rounded pea gravel moves underfoot; compactable decomposed granite behaves differently.
Compare layer depths →Driveways
Use the driveway plan's separate base and surface thicknesses. Local soil, traffic, drainage, and aggregate specification decide the build; one universal depth will not fit every site.
Plan a driveway →Drainage and creek beds
Stone size, channel shape, pipe, and drainage design change the quantity. For a pipe trench, subtract pipe displacement and use the specified washed aggregate.
Estimate drain rock →Shape changes performance
Angular stone and rounded rock are not interchangeable
Angular crushed stone can interlock when appropriately graded and compacted. Smooth river rock rolls and shifts more easily, making it better suited to decorative beds than a vehicle surface. Clean stone has open spaces for drainage; dense graded base contains fines that help it bind. The right choice depends on the project, not just its color.
Compare particle shapes →Allowances explained
Use extra material and compaction deliberately
The default 10% is an adjustable planning cushion for low spots and measurement error, not a guaranteed requirement. If you are estimating a compacted layer of crusher run or other material with fines, the Advanced Controls can apply an additional loose-to-finished volume factor. Keep that factor separate from the ordinary extra allowance, and confirm the target compacted thickness with the project's specification or supplier.
See compactable base material →Before checkout
Buy by the unit the seller actually uses
Compare the delivered total for your project. Vehicle payload and access limits vary; check the vehicle rating and supplier loading policy before choosing pickup.
Compare bulk and bagged rock →Prepare the site
The calculator estimates material, not the whole installation
Mark the boundary, measure in sections, check finished grade and drainage, and plan how the stone will be contained. Uneven soil can use more material than a flat rectangle suggests. Calculate edging, fabric, base, and visible stone separately where your design calls for them.
Read the installation guide →Final order check
Four details worth confirming
- Measure the actual footprint, including curves or separate beds. Do not mistake a radius for a diameter.
- Enter the finished stone depth, and estimate a compacted base as a separate material layer.
- Match the seller's unit: cubic yards, short tons, or bags with a stated cubic-foot yield.
- Ask for the supplier's density, availability, delivery minimum, and space needed to unload.
How the estimate is grounded
The volume math is geometry. The material densities are editable starting estimates, not measured values for a particular quarry load. Penn State's materials calculator also advises using local supplier factors. ASTM C29/C29M describes a way to measure aggregate bulk density under defined conditions; naming the method does not certify this site's defaults. For bag sizing, check the manufacturer's published cubic-foot yield, such as SAKRETE's product data.