Rock Calculator
Your comprehensive guide and planning resource
Use this rock calculator to estimate the exact amount of landscaping rock, gravel, or stone your project requires in cubic yards, tons, pounds, and bags — based on your area dimensions, desired depth, and material type. Enter your project measurements below and get instant, accurate results.
Rock Calculator
Accurate material conversions with customizable density & cost analysis
This free rock calculator supports rectangular, circular, triangular, and trench-shaped project areas. Built-in density presets cover river rock, pea gravel, crushed stone, lava rock, decomposed granite, limestone, sand, and base rock. Select your material, and the tool auto-fills the correct bulk density for precise weight conversion. An optional cost estimator calculates your total project expense when you enter a price per ton or per cubic yard.
How to Calculate Landscaping Rock
Calculating how much landscaping rock you need requires seven steps. This method works for driveways, garden beds, pathways, French drains, retaining walls, fire pits, and every other aggregate project.
- Measure your area — Find the length and width of your project space in feet using a tape measure. For irregular shapes, break the area into smaller rectangles, triangles, or circles and calculate each separately.
- Choose your depth — Standard landscaping depth is 2 to 3 inches for decorative ground cover. Driveways and paver foundations need 4 to 6 inches. French drains require 8 to 12 inches.
- Convert depth to feet — Divide your depth in inches by 12. Example: 3 inches ÷ 12 = 0.25 feet.
- Calculate cubic feet — Multiply length × width × depth (all in feet) to get total volume in cubic feet.
- Convert to cubic yards — Divide your total cubic feet by 27. One cubic yard contains exactly 27 cubic feet.
- Convert to tons — Multiply cubic yards by the material's bulk density. Gravel and stone typically weigh between 1.2 and 1.7 tons per cubic yard depending on type and particle size.
- Add 10–15% for waste — Account for compaction, uneven terrain, delivery settling, and spillage by ordering extra material beyond your base calculation.
💡 Key Fact: 1 cubic yard = 27 cubic feet. At a 2-inch depth, 1 cubic yard of rock covers approximately 162 square feet of surface area. At 3 inches deep, coverage drops to 108 square feet per cubic yard. These two numbers serve as reliable mental shortcuts for quick field estimates.
Rock Calculator Formulas by Shape
Volume formulas change based on the geometric shape of your project area. Below are the exact calculations this rock calculator uses for each supported shape.
Rectangle — Patios, Driveways, Garden Beds, Walkways
Formula:
Length (ft) × Width (ft) × Depth (ft) ÷ 27 = Cubic Yards
Worked Example: A 20 ft × 15 ft rectangular patio area with a 2-inch gravel layer:
- Surface area: 20 × 15 = 300 square feet
- Depth converted: 2 ÷ 12 = 0.167 feet
- Volume: 300 × 0.167 = 50.1 cubic feet
- Cubic yards: 50.1 ÷ 27 = 1.85 cubic yards
- Weight at 1.4 tons per cubic yard (standard gravel): 1.85 × 1.4 = 2.59 tons
- With 10% waste: 2.59 × 1.10 = 2.85 tons to order
This formula applies to rectangular driveways, parking pads, walkways, flower beds, patio areas, and slabs.
Circle — Fire Pits, Tree Rings, Round Islands, Circular Beds
Formula:
π × radius² × depth (ft) ÷ 27 = Cubic Yards
Worked Example: A 10-foot diameter circular fire pit area at 3-inch depth:
- Radius: 10 ÷ 2 = 5 feet
- Area: 3.14 × 25 = 78.5 square feet
- Depth converted: 3 ÷ 12 = 0.25 feet
- Volume: 78.5 × 0.25 = 19.63 cubic feet
- Cubic yards: 19.63 ÷ 27 = 0.73 cubic yards
The radius equals half the diameter. Measure across the widest point of your circle, then divide by two.
Triangle — Corner Beds, Angled Borders, Irregular Sections
Formula:
(Base × Height ÷ 2) × Depth (ft) ÷ 27 = Cubic Yards
Worked Example: A triangular corner garden bed with a 12-foot base and 8-foot height, at 3-inch depth:
- Area: (12 × 8) ÷ 2 = 48 square feet
- Depth converted: 3 ÷ 12 = 0.25 feet
- Volume: 48 × 0.25 = 12 cubic feet
- Cubic yards: 12 ÷ 27 = 0.44 cubic yards
Trench — French Drains, Edging, Utility Lines, Irrigation Channels
Formula:
Trench Length (ft) × Trench Width (ft) × Depth (ft) ÷ 27 = Cubic Yards
Worked Example: A 40-foot French drain trench, 1.5 feet wide, 12 inches deep:
- Volume: 40 × 1.5 × 1.0 = 60 cubic feet
- Cubic yards: 60 ÷ 27 = 2.22 cubic yards
- Weight at 1.5 tons per cubic yard (washed gravel): 2.22 × 1.5 = 3.33 tons
💡 Tip: For L-shaped areas, U-shaped beds, or any irregular layout, split your project into individual rectangles, triangles, or circles. Calculate each section separately, then add all volumes together for your total material requirement.
Rock Material Density Chart — Tons per Cubic Yard
Different rock materials have different bulk densities because of variations in particle size, stone shape, porosity, and air space between individual pieces. Bulk density represents how heavy a loose pile of material is — not the density of a single solid stone.
| Material | Tons per Cubic Yard | Lbs per Cubic Yard | Bulk Density (kg/m³) |
|---|---|---|---|
| Sand | 1.10 – 1.25 | 2,200 – 2,500 | 1,550 |
| Landscape Gravel | 1.25 – 1.35 | 2,500 – 2,700 | 1,600 |
| Pea Gravel | 1.40 – 1.60 | 2,800 – 3,200 | 1,788 |
| River Rock | 1.40 – 1.75 | 2,800 – 3,500 | 1,425 – 1,650 |
| Crushed Stone | 1.35 – 1.70 | 2,700 – 3,400 | 1,750 |
| Lava Rock | 1.20 – 1.40 | 2,400 – 2,800 | 1,200 |
| Washed Gravel | 1.40 – 1.60 | 2,800 – 3,200 | 1,500 |
| Limestone | 1.20 – 1.50 | 2,400 – 3,000 | 1,550 |
| Crushed Granite | 1.30 – 1.55 | 2,600 – 3,100 | 1,320 |
| Decomposed Granite | 1.35 – 1.50 | 2,700 – 3,000 | 1,400 |
| Base Rock (Class II) | 1.45 – 1.65 | 2,900 – 3,300 | 1,700 |
| Rip Rap | 1.25 – 1.50 | 2,500 – 3,000 | 1,500 |
| Cobblestone | 1.40 – 1.60 | 2,800 – 3,200 | 1,550 |
💡 Key Fact: Solid granite weighs approximately 2,700 kg/m³ as a single block. Loose, crushed granite that you purchase by the cubic yard weighs only about 1,320 kg/m³ because of air gaps between particles. Always use bulk density — not solid density — for material ordering calculations. Using solid density produces an estimate that is roughly double the actual amount needed.
💡 Tip: Wet material weighs 10 to 15% more than dry material due to absorbed water. If your supplier loads material right after rain, your weight ticket will read higher than expected even though you received the same volume. Confirm with your supplier whether their pricing accounts for moisture variation.
Recommended Rock Depths by Project Type
Depth determines the stability, visual completeness, and long-term performance of your rock installation. Too shallow leads to bare spots, weed breakthrough, and material displacement. Too deep wastes money without added benefit.
| Project Type | Recommended Depth | Best Material Choices |
|---|---|---|
| Decorative ground cover | 2 – 3 inches | River rock, pea gravel, lava rock, polished pebbles |
| Garden beds and flower beds | 2 – 3 inches | Decorative stone, 1–3 inch river rock, Mexican pebbles |
| Walkways and pathways | 2 – 3 inches | Pea gravel, decomposed granite, crushed stone |
| Dry creek beds | 3 – 5 inches | Mixed river rock (1–3 inch and 3–5 inch combination) |
| Gravel driveways (surface) | 4 – 6 inches | Crushed stone, road gravel, ¾-inch angular rock |
| Paver base and foundation | 4 – 6 inches | Class II base rock, crushed limestone, traffic bond |
| Decomposed granite driveways | 4 inches minimum | Decomposed granite (mechanically compacted) |
| French drain backfill | 8 – 12 inches | Washed gravel, ¾-inch drain rock (no fines) |
| Retaining wall backfill | 12+ inches | ¾-inch washed gravel, clean drain rock |
| Concrete sand leveling layer | 1 inch | Concrete sand (screeded flat over compacted base) |
| Erosion control and rip rap | 6 – 12 inches | Rip rap, 4–8 inch cobble, large angular stone |
| Fire pit decorative fill | 2 – 4 inches | Lava rock, fire glass, tumbled lava stone |
💡 Key Fact: The Interlocking Concrete Pavement Institute (ICPI) specifies a minimum 4-inch compacted aggregate base for pedestrian paver installations and a minimum 6-inch compacted base for vehicular paver applications such as driveways. The National Cooperative Highway Research Program recommends similar depths for residential aggregate surfaces subjected to regular vehicle traffic.
💡 Tip: For high-traffic areas like driveways and parking pads, compact your base layer with a plate compactor or vibratory roller before adding the finished surface layer. Crushed stone compresses by approximately 15 to 20% during compaction. Increase your base rock order by this percentage to achieve the required finished depth after compaction.
Rock Size Guide — Which Size for Which Application
Rock size directly affects four things: drainage speed, surface walkability, compaction ability, and visual scale. Smaller angular stones lock together tightly for firm surfaces. Larger rounded stones stay loose and allow water to flow freely between them.
| Rock Size | Common Names | Best Applications |
|---|---|---|
| ¼ inch | Decomposed granite, stone dust, screenings, crusher fines | Pathways, between pavers, compacted trails, bocce courts |
| ⅜ – ½ inch | Pea gravel, pea rock, small rounded stone | Walkways, dog runs, playground surfaces, ground cover, drainage backfill |
| ¾ inch | Crushed stone, drain rock, #57 stone, clean rock | French drains, paver base, pipe bedding, drainage trenches, utility backfill |
| 1 – 2 inch | Medium river rock, crushed gravel, washed rock | Decorative beds, tree rings, garden borders, mild erosion control |
| 1 – 3 inch | Standard river rock, landscape rock | Landscaping borders, garden beds, decorative ground cover, dry creek beds |
| 3 – 5 inch | Large river rock, cobble, large decorative stone | Dry creek beds, slope erosion control, accent features, water features |
| 4 – 8 inch | Rip rap, large cobble, armor stone | Heavy erosion control, slope stabilization, channel lining, retaining support |
| 6 – 12+ inch | Boulders, oversize rip rap, landscape boulders | Retaining structures, water features, property focal points, slope anchoring |
💡 Key Fact: ¾-inch crushed stone (#57 stone) is the single most widely used construction aggregate in the United States. Its angular, fractured edges interlock during compaction to form a stable, load-bearing surface. This one material serves as French drain fill, paver foundation base, driveway subbase, pipe bedding, and utility trench backfill — making it the most cost-effective choice for multi-purpose projects.
Quick Coverage Estimator Table
This table provides fast estimates without running the full formula. All values assume a 2-inch depth and include a standard 10% waste factor already calculated into the numbers.
| Project Area | Square Footage | Cubic Yards Needed | Estimated Tons (at 1.4 t/yd³) |
|---|---|---|---|
| 5 ft × 10 ft | 50 sq ft | 0.34 yd³ | 0.48 tons |
| 10 ft × 10 ft | 100 sq ft | 0.68 yd³ | 0.95 tons |
| 10 ft × 20 ft | 200 sq ft | 1.36 yd³ | 1.90 tons |
| 12 ft × 12 ft | 144 sq ft | 0.98 yd³ | 1.37 tons |
| 15 ft × 15 ft | 225 sq ft | 1.53 yd³ | 2.14 tons |
| 20 ft × 20 ft | 400 sq ft | 2.72 yd³ | 3.81 tons |
| 20 ft × 30 ft | 600 sq ft | 4.07 yd³ | 5.70 tons |
| 20 ft × 50 ft | 1,000 sq ft | 6.79 yd³ | 9.51 tons |
| 30 ft × 50 ft | 1,500 sq ft | 10.19 yd³ | 14.26 tons |
| 50 ft × 50 ft | 2,500 sq ft | 16.98 yd³ | 23.77 tons |
💡 Quick Shortcut: For a 2-inch depth, divide your total square footage by 150 to estimate cubic yards. For 3 inches, divide by 100. For 4 inches, divide by 75. These mental shortcuts produce results within 5 to 10% of the full formula — accurate enough for preliminary budgeting before you place a final order.
Tons to Cubic Yards Conversion Table for Rock
Material suppliers sell rock either by weight (tons) or by volume (cubic yards). The conversion between these two units depends entirely on bulk density, which changes with every material type. This table gives you the direct conversion factor for each common aggregate.
| Material | 1 Cubic Yard = (Tons) | 1 Ton = (Cubic Yards) |
|---|---|---|
| Sand | 1.18 tons | 0.85 yd³ |
| Gravel (general) | 1.30 tons | 0.77 yd³ |
| Pea Gravel | 1.50 tons | 0.67 yd³ |
| River Rock | 1.55 tons | 0.65 yd³ |
| Crushed Stone | 1.50 tons | 0.67 yd³ |
| Lava Rock | 1.30 tons | 0.77 yd³ |
| Limestone | 1.35 tons | 0.74 yd³ |
| Base Rock | 1.55 tons | 0.65 yd³ |
| Decomposed Granite | 1.42 tons | 0.70 yd³ |
| Rip Rap | 1.38 tons | 0.73 yd³ |
💡 Key Fact: A standard tandem-axle dump truck carries approximately 12 to 15 tons of aggregate material per load, which equals roughly 8 to 10 cubic yards. A single-axle dump truck holds 5 to 7 tons (3 to 5 cubic yards). Calculating your total tonnage before ordering lets you determine exactly how many delivery trips your project requires and helps you avoid unexpected split-load surcharges from your supplier.
Bags vs. Bulk — When to Buy Bagged Rock vs. Bulk Delivery
The decision between bagged rock from a retail store and bulk delivery from a landscape supply yard affects both your budget and your effort level significantly.
| Factor | Bagged Rock | Bulk Delivery |
|---|---|---|
| Ideal project size | Under 0.5 cubic yards (less than ½ ton) | Over 1 cubic yard (more than 1 ton) |
| Average material cost | $4 – $8 per 50-lb bag | $25 – $80 per ton |
| Delivery fee | None — self-service | $50 – $150 per truckload |
| Minimum order | 1 bag | Typically 1 to 3 tons |
| Waste generated | Very low | Slightly higher (settling during transport) |
| Physical effort | You load, transport, and carry every bag | Material delivered and dumped at your site |
| Cost per ton equivalent | $160 – $320 per ton | $25 – $80 per ton |
One 50-pound bag of standard landscaping rock covers approximately 2 to 3 square feet at a 2-inch depth. Once your calculation exceeds 20 bags (1,000 pounds total), bulk ordering is almost always the more economical choice — often 50 to 70% cheaper per ton than bagged material from a home improvement retailer.
💡 Tip: Contact your local landscape supply yard or rock quarry directly for bulk pricing. Many suppliers waive the delivery fee on orders above 5 tons. Ask whether they sell by the ton (weighed on a truck scale) or by the "scoop" (a front-end loader bucket that holds roughly ½ cubic yard). Knowing their measurement method helps you compare quotes accurately across different vendors.
How to Use This Rock Calculator
Follow these steps to get accurate results from the calculator tool at the top of this page:
- Select your project shape — Choose rectangle, circle, triangle, or trench from the shape tabs. The input fields adjust automatically based on your selection.
- Enter dimensions — Type your length, width (or diameter for circles), and desired depth. Use the unit dropdown to select feet, inches, yards, or meters.
- Choose material type — Select your rock material from the dropdown menu. The bulk density field fills automatically with the correct preset value. You can override it manually if you know your supplier's specific density.
- Add cost details (optional) — Enter price per ton or per cubic yard, delivery fee, and tax percentage to calculate total estimated project cost.
- Click Calculate — The results panel instantly displays your volume in cubic yards and cubic feet, weight in tons and pounds, coverage in square feet, number of 50-lb bags needed, and estimated total cost.
- Save, print, or export — Use the action buttons to save your calculation for reference, print a clean summary, or export data as a CSV file for purchase orders.
The calculator includes a default 10% waste factor. For projects on sloped or uneven ground, manually increase depth input by 15 to 20% to compensate for terrain irregularities.
Reverse Coverage Calculator — How Much Area Will My Rock Cover?
If you already purchased material and need to know how much ground it will cover at your desired depth, use this reverse formula:
Formula:
Area (sq ft) = Cubic Yards × 27 ÷ Depth (in feet)
Worked Example: You have 3 cubic yards of pea gravel and want to spread it 2 inches deep:
- Depth converted: 2 ÷ 12 = 0.167 feet
- Coverage: 3 × 27 ÷ 0.167 = 485 square feet
Use this reference to see how far 1 cubic yard of any rock stretches at different depths:
| Depth Applied | Area Covered per 1 Cubic Yard |
|---|---|
| 1 inch | 324 sq ft |
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
| 6 inches | 54 sq ft |
| 12 inches | 27 sq ft |
This reverse calculation is particularly useful when your supplier delivers slightly more or less material than ordered, or when you have leftover rock from a previous project and want to determine whether it covers a new area adequately.
Rock Calculator for Specific Projects
Each project type has unique material requirements, depth standards, and calculation considerations. Below are the five most common project-specific calculations.
Driveway Rock Calculator
A properly built Gravel Driveway uses a layered system — a coarse angular base for stability topped with a finer surface for drivability.
- Base layer: 4 inches of crushed stone or Class II base rock (compacted with a plate compactor)
- Surface layer: 2 inches of ¾-inch crushed gravel, road gravel, or decomposed granite
- Combined total depth: 5 to 6 inches
Worked Example: A 12 ft × 50 ft residential driveway at 5-inch total depth:
- Surface area: 600 square feet
- Depth converted: 5 ÷ 12 = 0.417 feet
- Volume: 600 × 0.417 ÷ 27 = 9.26 cubic yards
- Weight at 1.5 tons per cubic yard: 9.26 × 1.5 = 13.89 tons
- Add 20% for compaction: 13.89 × 1.20 = 16.67 tons total order
Crushed stone driveways compact by 15 to 20% when mechanically compressed. Without increasing your order by this compaction percentage, your finished driveway will be thinner than intended and more susceptible to rutting.
French Drain Rock Calculator
French drains collect and redirect groundwater away from foundations, basements, and saturated low areas. They require clean washed gravel with no fine particles (no "fines") to maintain drainage flow.
- Material: ¾-inch washed gravel or drain rock
- Trench dimensions: 6 to 12 inches wide, 12 to 18 inches deep, variable length
- Key requirement: No crusher fines, dust, or clay content
Worked Example: A 60-foot French drain, 12 inches wide, 14 inches deep:
- Width converted: 12 ÷ 12 = 1 foot
- Depth converted: 14 ÷ 12 = 1.167 feet
- Volume: 60 × 1 × 1.167 = 70 cubic feet
- Cubic yards: 70 ÷ 27 = 2.59 yd³
- Weight at 1.5 tons per cubic yard: 2.59 × 1.5 = 3.89 tons
Wrap your perforated drain pipe in non-woven geotextile filter fabric before placing it in the gravel-filled trench. This prevents soil particles from migrating into the drain and clogging the perforations over time. Place 2 to 3 inches of gravel below the pipe, center the pipe, then backfill with gravel to within 3 to 4 inches of the surface.
Fire Pit Rock Calculator
Gas fire pits use decorative lava rock or tempered fire glass to cover the burner ring and create an attractive finished appearance. The fill material must be rated for high heat exposure.
- Material: Lava rock, fire glass, or fire-rated decorite
- Depth: 2 to 4 inches above the burner pan
- Shape: Typically circular
Worked Example: A 36-inch (3-foot) diameter fire pit bowl at 3-inch depth:
- Radius: 3 ÷ 2 = 1.5 feet
- Volume: 3.14 × 2.25 × 0.25 = 1.77 cubic feet
- Lava rock weight at approximately 75 lbs per cubic foot: 1.77 × 75 = 133 pounds (about three 50-lb bags)
Lava rock has a bulk density of approximately 1,200 kg/m³ — significantly lighter than river rock at 1,425 to 1,650 kg/m³. This lower density means you need less total weight to fill the same volume, making lava rock economical for fire features despite its higher per-pound price.
River Rock Calculator for Landscaping
River rock is the most popular decorative stone for residential landscaping projects across the United States. Its naturally smooth, rounded surface and variety of earth-tone colors make it suitable for garden borders, dry creek beds, tree rings, ground cover, and decorative accents.
- Most popular sizes: 1–3 inch (general landscaping), 3–5 inch (visual accent and erosion control)
- Standard depth: 2 to 3 inches for decorative applications
- Bulk density: 1.40 to 1.75 tons per cubic yard (varies directly with stone size — larger stones have bigger air gaps and lower bulk density)
Worked Example: A 10 ft × 20 ft garden bed covered with 3-inch river rock:
- Surface area: 200 square feet
- Depth converted: 3 ÷ 12 = 0.25 feet
- Volume: 200 × 0.25 ÷ 27 = 1.85 cubic yards
- Weight at 1.55 tons per cubic yard: 1.85 × 1.55 = 2.87 tons
- With 10% waste: 3.16 tons to order
When using large 3–5 inch river rock, expect to see more ground visible between stones compared to smaller 1–2 inch material at the same depth. For complete ground coverage with larger stones, increase depth to 4 inches or choose a smaller size grade.
Base Rock Calculator for Pavers and Foundations
Every paver patio, walkway, and driveway requires a compacted aggregate base layer for structural integrity. Without a proper base, pavers shift, settle unevenly, and crack within the first two seasons.
- Material: Class II base rock, crushed limestone, or traffic bond
- Depth: 4 to 6 inches (compacted measurement)
- Sand layer: 1 inch of concrete sand on top (for leveling and bedding pavers)
Worked Example: A 14 ft × 14 ft patio foundation at 5-inch compacted base depth:
- Surface area: 196 square feet
- Base rock depth converted: 5 ÷ 12 = 0.417 feet
- Base volume: 196 × 0.417 ÷ 27 = 3.03 cubic yards
- Add 20% compaction factor: 3.03 × 1.20 = 3.64 cubic yards
- Weight at 1.55 tons per cubic yard: 3.64 × 1.55 = 5.64 tons of base rock
- Sand layer: 196 × 0.083 ÷ 27 = 0.60 cubic yards (approximately 0.71 tons)
💡 Key Fact: Base rock compresses by 15 to 20% during mechanical compaction. If your design calls for a 4-inch compacted depth, you must spread approximately 5 inches of loose material before compacting. Failing to account for this compression ratio is one of the most common ordering mistakes in paver installation projects.
Common Mistakes When Calculating Rock
Avoid these six errors that lead homeowners and contractors to order too much or too little material:
- Forgetting to convert inches to feet before multiplying — Depth must be expressed in feet when used in the formula. Divide inches by 12. Skipping this conversion produces a result that is 12 times too high, leading to a massive over-order that cannot easily be returned.
- Ignoring the compaction factor for base materials — Crushed stone and base rock compact by 15 to 20% under a plate compactor or roller. A formula result of 5 cubic yards means you need to order at least 6 cubic yards to achieve the target compacted depth.
- Using solid rock density instead of bulk density — A single block of granite weighs approximately 2,700 kg/m³. A loose pile of crushed granite weighs only about 1,320 kg/m³ because of air space between particles. Bulk density is the only correct value for ordering calculations.
- Ignoring terrain irregularity — Slopes, low spots, root humps, and drainage depressions all consume extra material beyond what a flat-ground calculation predicts. Add 10 to 15% for any project area that is not perfectly level and graded.
- Ordering the exact calculated amount with zero buffer — Rock shifts during truck transport, spreads slightly beyond borders during installation, and settles into soft subgrade over time. A minimum 10% waste factor protects against under-ordering. For projects under 2 tons, use 15%.
- Confusing cubic yards with square yards or square feet — Cubic yards measure three-dimensional volume (length × width × depth). Square feet and square yards measure only two-dimensional surface area. Rock suppliers sell by volume (cubic yards) or weight (tons) — never by square footage alone.
Frequently Asked Questions
At a 2-inch depth, 100 square feet requires approximately 0.62 cubic yards of material, which equals about 0.87 tons of standard gravel. At a 3-inch depth, the same area needs 0.93 cubic yards (1.30 tons). Add 10% to these numbers for your actual order quantity. The formula is: square footage × depth in feet ÷ 27 = cubic yards.
One cubic yard of rock weighs between 1.2 and 1.75 tons depending on material type and particle size. Lightweight lava rock averages 1.2 to 1.4 tons per cubic yard. Pea gravel and river rock average 1.4 to 1.6 tons per cubic yard. Dense crushed stone ranges from 1.5 to 1.7 tons per cubic yard. The exact weight varies based on moisture content, quarry source, and stone gradation.
At a 2-inch depth, 1 ton of standard gravel (density of approximately 1.4 tons per cubic yard) covers roughly 115 square feet. At 3 inches deep, that same ton covers approximately 77 square feet. The formula is: (1 ÷ material density in tons per yd³) × 27 ÷ depth in feet = square feet of coverage.
Multiply your total cubic yards by the material's bulk density in tons per cubic yard. Formula: Cubic Yards × Density = Total Tons. For example, 4 cubic yards of pea gravel at 1.5 tons per cubic yard equals 6.0 tons. Check the material density chart above for your specific rock type's conversion factor.
Decorative ground cover, garden beds, and pathways need 2 to 3 inches of depth. Gravel driveways and paver base foundations need 4 to 6 inches. French drain backfill needs 8 to 12 inches. Retaining wall drainage backfill needs 12 inches or more. Insufficient depth causes weed penetration, exposed ground, material displacement from foot traffic, and inadequate drainage capacity.
River rock costs between $45 and $130 per cubic yard across most US markets, varying by stone size, color uniformity, and regional supply availability. Delivery typically adds $50 to $150 per truckload depending on distance from the quarry. Hand-selected, uniformly colored, or polished river rock carries a significant premium over standard mixed-color quarry material.
A standard tandem-axle dump truck carries 12 to 15 tons of aggregate material per load, equaling approximately 8 to 10 cubic yards. A single-axle dump truck holds 5 to 7 tons (3 to 5 cubic yards). A tri-axle truck can carry up to 20 tons. Knowing your total tonnage tells you exactly how many truckloads to schedule and helps you avoid unexpected partial-load delivery surcharges.
Cubic yards measure volume — the three-dimensional space material occupies. Tons measure weight — how heavy the material is. The same 1 cubic yard of different materials weighs different amounts because of density variation. One cubic yard of pea gravel weighs about 1.5 tons. One cubic yard of lava rock weighs only about 1.3 tons. Same volume, different weight — connected by the density conversion factor.
Measure your driveway length and width in feet. Use a total depth of 4 to 6 inches (base plus surface combined). Multiply length × width × depth in feet, then divide by 27 for cubic yards. Example: A 12 ft × 40 ft driveway at 5 inches deep needs 480 × 0.417 ÷ 27 = 7.4 cubic yards, or approximately 11 tons of crushed stone. Add 15 to 20% for compaction, bringing your final order to approximately 13 tons.
Measure the full diameter across the widest point. Divide by 2 to get the radius. Apply the formula: π × radius² × depth (in feet) ÷ 27 = cubic yards. Example: An 8-foot diameter circle at 3 inches deep equals 3.14 × 16 × 0.25 ÷ 27 = 0.47 cubic yards. Multiply by your chosen material's density to convert cubic yards into tons for ordering.
Divide your L-shaped area into two separate rectangles. Calculate the cubic yards for each rectangle individually using length × width × depth ÷ 27. Then add both results together for your total volume requirement. This same "divide and add" method works for any irregular shape — U-shapes, curves, or multi-section layouts.