Stone Calculator
Stone Calculator
Typical depths: paths 2–3 in, driveways 4–6 in, drainage 8–12 in
10% recommended to account for spillage and uneven spreading
Add 20–30% if material will be mechanically compacted
Optional: Pricing
Enter Your Project Dimensions
Select a shape, enter your area dimensions and depth, choose your stone type, and see volume, weight, bag count, and cost instantly.
Multi-Zone Calculator
Calculate stone, gravel, and aggregate volume, weight, and cost for any project shape
Planning a landscaping or construction project that requires stone, gravel, or crushed aggregate? Our free Stone Calculator takes the guesswork out of ordering materials. Whether you are building a driveway, laying a garden path, constructing a patio base, filling a French drain, or creating decorative ground cover, knowing exactly how much stone you need prevents costly over-ordering or frustrating mid-project shortages. This calculator supports four common area shapes — rectangle, circle, triangle, and trench — and outputs results in every unit system you may encounter: cubic feet, cubic yards, cubic meters, pounds, short tons, kilograms, and metric tonnes. It also estimates the number of bags needed for smaller projects and the number of pickup or dump truck loads required for larger orders. Understanding what you need before calling a supplier saves both time and money. Stone and gravel are typically sold by the ton or cubic yard, and prices vary widely by material type and local market. By entering an optional price per ton or per cubic yard, you can get a real-time cost estimate that includes delivery fees and sales tax — giving you the total landed cost before you make any purchases. The calculator includes 16 material presets covering the most common types of stone and aggregate: crushed stone in two size ranges, pea gravel, river rock, standard gravel, gravel with sand, limestone, granite, lava rock, cobblestones, rip rap, stone dust, Type 1 MOT road base, #57 stone, dry sand, and wet sand. Each preset uses industry-standard bulk density values drawn from contractor manuals and civil engineering references. If you know your specific material's density, you can also enter a custom value. A waste factor (default 10%) is automatically applied to account for spillage during delivery, uneven spreading, and settling over time. This is the industry-standard recommendation from suppliers and contractors. You can adjust the waste factor up or down, or add a compaction factor for applications where the stone will be mechanically compacted, such as road bases or patio sub-layers. For planning deliveries, the calculator shows you how many standard dump truck loads (13-ton capacity) and pickup truck loads (1 cubic yard capacity) your order requires. This helps coordinate deliveries and budget for hauling costs. The coverage area output tells you exactly how many square feet your calculated volume will cover at the depth you specified. All calculations run instantly in your browser. No account is required, and no data is stored. You can export your results to a CSV file for inclusion in project spreadsheets or print a results summary to share with your contractor or supplier. The depth recommendation guide at the bottom of your results provides standard application depths for common use cases, helping you confirm you have chosen an appropriate depth for your project type.
Understanding Stone and Gravel Calculations
Accurate material estimation requires understanding volume, density, and the difference between loose and compacted measurements. This section explains the key concepts behind stone calculations.
How Stone Volume Is Calculated
Stone volume is calculated by multiplying the area of your project by the desired depth. For rectangular areas, this is simply length multiplied by width multiplied by depth. For circular areas, the formula uses pi multiplied by the radius squared multiplied by depth. Triangular areas use half the base times height times depth. Trench calculations use the trench length multiplied by its width and depth. All dimension inputs are converted to feet before calculation, then the result is divided by 27 to get cubic yards (since there are 27 cubic feet per cubic yard). Cubic meters are calculated by multiplying cubic yards by 0.764555. The waste factor is applied as a percentage increase to the base volume, ensuring you order enough to account for real-world losses.
Material Density and Weight
Stone weight depends on the material's bulk density — the mass of the loose material per unit volume. Density varies significantly between stone types. Lava rock is very light at roughly 0.78 tons per cubic yard, making it ideal for slopes where weight is a concern. Rip rap is very dense at around 1.85 tons per cubic yard, which is why it is used for heavy-duty erosion control. Most crushed stone and gravel falls between 1.4 and 1.7 tons per cubic yard. Knowing the weight is critical for planning deliveries, because trucks have weight limits, and structural applications require knowing the load being applied to the ground or a base course.
Waste and Compaction Factors
The waste factor accounts for inevitable losses during delivery, spreading, and settling. Industry consensus is to add 10% as a standard allowance. Conservative estimates of 5–6% may be appropriate for experienced crews with precise delivery drops, while 15% may be prudent for difficult site access or complex shapes. The compaction factor is separate and accounts for the fact that loose stone delivered by the truck is typically 20–30% less dense than compacted stone. If you are building a road base or patio sub-layer that will be mechanically compacted, adding a 20–30% compaction allowance ensures you will have enough material once the plate compactor has finished. For decorative applications that are not compacted, the compaction factor should remain at zero.
Choosing the Right Stone Type
Stone type selection matters both for function and aesthetics. Crushed stone is the most versatile material for base layers, drainage, and general fill — its angular edges interlock when compacted, creating a stable surface. Pea gravel is smooth and rounded, making it comfortable underfoot for paths and decorative areas, but it rolls and is unsuitable for driveways or areas requiring stability. River rock offers a natural look for landscaping but is also poorly suited for high-traffic areas. Rip rap and large cobblestones are used for erosion control along water features and slopes. Stone dust compacts to a very hard surface and is often used as the top layer under pavers. Lava rock is the best choice for weight-sensitive applications such as green roofs or steep slopes.
Stone & Gravel Calculation Formulas
Volume (Rectangular Area)
Volume (cu ft) = Length (ft) × Width (ft) × Depth (ft)
Multiply the three dimensions in feet. For depth in inches, divide by 12 first. Divide the result by 27 to convert cubic feet to cubic yards.
Weight from Volume
Weight (tons) = Volume (cu yd) × Density (lbs/cu yd) / 2000
Multiply the volume in cubic yards by the material's bulk density in pounds per cubic yard, then divide by 2,000 to convert to short tons.
Volume with Waste and Compaction
Adjusted Volume = Base Volume × (1 + Waste% / 100) × (1 + Compaction% / 100)
Apply waste factor first (typically 10%) then compaction factor (20–30% for mechanically compacted bases) to the base volume.
Circular Area Volume
Volume (cu ft) = π × (Diameter / 2)² × Depth
For circular project areas such as tree rings or fire pit bases, use the circle area formula with all measurements in feet.
Stone & Gravel Reference Tables
Stone Types: Density and Coverage
Bulk densities and approximate coverage per ton at common depths. Coverage varies with stone shape and settling.
| Material | Density (lbs/cu yd) | Tons/cu yd | Coverage at 2" (sq ft/ton) | Coverage at 4" (sq ft/ton) |
|---|---|---|---|---|
| Crushed Stone (1/4"–2") | 2700 | 1.35 | 130 | 65 |
| Pea Gravel | 2800 | 1.40 | 125 | 63 |
| River Rock | 2600 | 1.30 | 135 | 68 |
| Gravel (3/4"–2") | 2800 | 1.40 | 125 | 63 |
| Limestone | 2800 | 1.40 | 125 | 63 |
| Granite | 2900 | 1.45 | 120 | 60 |
| Lava Rock | 1560 | 0.78 | 225 | 112 |
| Rip Rap (6"–9") | 3700 | 1.85 | 95 | 47 |
| Stone Dust / Screenings | 2700 | 1.35 | 130 | 65 |
Common Applications and Recommended Depths
Standard depth recommendations for typical stone and gravel projects.
| Application | Recommended Depth | Best Stone Types |
|---|---|---|
| Decorative ground cover | 2–3 inches | Pea gravel, river rock, lava rock |
| Walking paths | 2–3 inches | Pea gravel, crushed stone (small) |
| Patio base | 4–6 inches | Crushed stone, Type 1 MOT |
| Driveway top layer | 3–4 inches | #57 stone, crushed stone |
| Driveway base | 6–8 inches | Crushed stone (large), Type 1 MOT |
| French drain fill | 8–12 inches | Washed gravel, #57 stone |
| Retaining wall backfill | 12+ inches | Crushed stone, gravel with sand |
Worked Examples
Crushed Stone for a 500 sq ft Driveway at 4" Depth
A rectangular driveway measures 50 feet long × 10 feet wide with a desired depth of 4 inches of crushed stone (density: 2,700 lbs/cu yd). Standard 10% waste factor, no compaction.
Convert depth to feet: 4 in ÷ 12 = 0.333 ft
Volume: 50 × 10 × 0.333 = 166.7 cu ft
Convert to cubic yards: 166.7 ÷ 27 = 6.17 cu yd
Apply 10% waste: 6.17 × 1.10 = 6.79 cu yd
Weight: 6.79 × 2,700 = 18,333 lbs ÷ 2,000 = 9.17 short tons
Order approximately 6.8 cubic yards or 9.2 tons of crushed stone. This requires one standard dump truck load (13-ton capacity).
Decorative River Rock for a Garden Bed
A circular garden bed has a diameter of 12 feet with a desired depth of 3 inches of river rock (density: 2,600 lbs/cu yd). Standard 10% waste.
Convert depth to feet: 3 in ÷ 12 = 0.25 ft
Circle area: π × (12/2)² = 113.1 sq ft
Volume: 113.1 × 0.25 = 28.27 cu ft
Convert to cubic yards: 28.27 ÷ 27 = 1.047 cu yd
Apply 10% waste: 1.047 × 1.10 = 1.15 cu yd
Weight: 1.15 × 2,600 = 2,990 lbs ÷ 2,000 = 1.50 short tons
Order approximately 1.2 cubic yards or 1.5 tons of river rock. At $65/ton, material cost is about $97.50 before delivery.
French Drain Trench Fill
A French drain trench is 60 feet long, 1 foot wide, and 1 foot deep, filled with washed gravel (density: 2,800 lbs/cu yd). 10% waste factor.
Volume: 60 × 1 × 1 = 60 cu ft
Convert to cubic yards: 60 ÷ 27 = 2.22 cu yd
Apply 10% waste: 2.22 × 1.10 = 2.44 cu yd
Weight: 2.44 × 2,800 = 6,832 lbs ÷ 2,000 = 3.42 short tons
Order approximately 2.5 cubic yards or 3.4 tons of washed gravel for the French drain.
How to Use the Stone Calculator
Select Your Area Shape
Choose the shape that best matches your project area: Rectangle for patios, driveways, and square garden beds; Circle for round features; Triangle for wedge-shaped areas; Trench for drainage channels or linear fills. Then enter the corresponding dimensions (length and width for rectangles, diameter for circles, base and height for triangles).
Enter Depth and Choose Stone Type
Enter the desired depth or thickness in your preferred unit. Common depths are 2–3 inches for decorative paths, 4–6 inches for driveways, and 8–12 inches for drainage. Select your stone or aggregate type from the dropdown to apply the correct bulk density. If your supplier lists a specific density, select Custom and enter it in pounds per cubic yard.
Adjust Waste and Compaction Factors
Leave the waste factor at the default 10% for most projects — this covers spillage during delivery and uneven spreading. If your stone will be mechanically compacted (road bases, patio sub-layers), add a compaction factor of 20–30% to ensure you have enough material after the plate compactor runs. Decorative surface applications do not need a compaction factor.
Add Pricing for Cost Estimate
Optionally enter your supplier's unit price per ton or per cubic yard to see a total material cost. Add a delivery fee and any applicable sales tax to get the full landed cost. Results update instantly. Use the Export CSV button to save your results for a project spreadsheet, or print a summary to share with your contractor or supplier.
Frequently Asked Questions
How many cubic yards of stone do I need for a 10x10 area at 4 inches deep?
A 10x10 foot area with a 4-inch (0.333 ft) depth requires 33.33 cubic feet of stone, which is 1.23 cubic yards (33.33 ÷ 27). With the standard 10% waste factor, you should order approximately 1.35 cubic yards. At a typical crushed stone density of about 1.55 tons per cubic yard, that works out to roughly 2.1 short tons. Always round up to the nearest half cubic yard when ordering to avoid running short on site. Use this calculator with your exact dimensions for a precise number before calling your supplier.
How many tons of gravel do I need per cubic yard?
The weight of gravel per cubic yard depends on the specific material. Standard gravel and crushed stone typically weighs 1.4 to 1.7 short tons per cubic yard, with 1.5 tons being the most common rule of thumb for general planning. Lighter materials like lava rock weigh around 0.78 tons per cubic yard, while denser materials like rip rap can exceed 1.85 tons per cubic yard. Always use the correct density for your specific material. This calculator includes preset densities for 16 common stone and aggregate types, or you can enter a custom density if your supplier provides one.
What is a standard waste factor for stone and gravel projects?
The industry-standard waste factor for stone and gravel projects is 10%, and this is the default used by most professional estimating tools. This accounts for material lost during delivery (the truck cannot place every stone perfectly), uneven spreading at the edges, and settling after the first rains or foot traffic. For complex shapes with many curves, difficult site access, or projects where stone must be cut around obstacles, increasing the waste factor to 12–15% is reasonable. Conservative projects with experienced crews and precise delivery may use 5–6%. For initial planning and supplier quotations, always use at least 10% to avoid running short.
What is the difference between a short ton and a metric tonne?
A short ton, used in the United States, equals 2,000 pounds. A metric tonne, used in most of the rest of the world and in scientific contexts, equals 1,000 kilograms or approximately 2,204.6 pounds. When ordering stone in the US, suppliers quote prices in short tons. When using metric units, quantities are in metric tonnes. The difference is about 10%: one metric tonne is roughly 1.1 short tons. This calculator shows results in both units so you can communicate clearly with suppliers regardless of which unit system they use. Always confirm with your supplier whether they quote in short tons or metric tonnes to avoid confusion when ordering.
How do I calculate how much stone I need for a French drain?
A French drain is calculated as a trench: multiply the trench length by its width and depth. For example, a French drain that is 50 feet long, 12 inches (1 foot) wide, and 12 inches (1 foot) deep requires 50 cubic feet of stone, or 1.85 cubic yards. A 10% waste factor brings this to about 2.04 cubic yards. At a crushed stone density of 1.55 tons per cubic yard, that is approximately 3.2 short tons. French drains typically use clean crushed stone or washed gravel in the 3/4 to 1.5 inch size range to allow water to flow freely around the perforated pipe while resisting soil infiltration. Select this calculator's Trench mode and enter your drain dimensions for an accurate material estimate.
How much does a truckload of gravel or crushed stone cost?
Gravel and crushed stone prices vary significantly by region, material type, and market conditions. In general, crushed stone costs between $25 and $55 per ton delivered, while pea gravel and river rock may range from $40 to $75 per ton due to additional processing. A standard dump truck carries approximately 13 to 15 short tons, so a single truckload of crushed stone typically costs $400 to $825 for material plus a $50 to $150 delivery fee, depending on distance. Premium decorative stones like lava rock or river rock can cost $75 to $120 per ton or more. Always get at least three quotes from local suppliers, as quarry proximity has a major impact on delivered price.
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