Gravel Calculator

How to Use the Gravel Calculator

Add each rectangular area with length, width, and depth. Select a material type for a density starting point (or choose Custom and enter density), set an optional allowance, and optionally enter a unit price with a pricing mode. Calculate to see area-by-area volumes, totals, estimated order weight, and cost when you provided a price.

Gravel Volume Formula

For a rectangular bed or pad:

Volume = Length × Width × Depth

All dimensions are converted to meters before multiplying so mixed US customary and metric inputs stay consistent. Totals are reported in cubic feet, cubic yards, and cubic meters.

Calculating Gravel Depth

Depth is often shallow compared with length and width. Enter inches or centimeters when that matches how you measure the bed. Typical decorative or driveway beds vary by project; use the depth your plan or installer specifies rather than a generic rule of thumb.

Cubic Yards vs Cubic Feet

One cubic yard equals 27 cubic feet. Suppliers often quote gravel by the cubic yard. This calculator reports both cubic yards and cubic feet (and cubic meters) from the same geometric volume.

Converting Gravel Volume to Weight

Estimated order mass uses order volume including allowance:

Mass (kg) = Order volume (m³) × Density (kg/m³)

Results also show metric tonnes (1000 kg) and US short tons (2000 lb = 907.18474 kg). Do not confuse volume units (cubic yards) with mass units (tons/tonnes).

Gravel Density and Material Types

Loose bulk density varies with stone type, size, moisture, and compaction. CostRafter’s material defaults are mid-range loose planning estimates you can edit:

• Crushed stone: about 1600 kg/m³ (~100 lb/ft³)
• Pea gravel: about 1540 kg/m³ (~96 lb/ft³)
• River rock: about 1600 kg/m³ (~100 lb/ft³)
• Decomposed granite: about 1680 kg/m³ (~105 lb/ft³)
• Custom: enter your own density in kg/m³ or lb/ft³

These are not supplier product specifications. Prefer scale-ticket or quarry densities when available.

How Much Extra Gravel Should You Order?

An optional allowance multiplies base volume:

Order volume = Base volume × (1 + allowance% ÷ 100)

The default is 10% (editable, range 0–30%). This is a planning estimate for compaction, uneven ground, or handling loss—not a universal recommendation. Follow your installer or supplier guidance when it differs.

Estimating Gravel Material Cost

Optional material cost uses one pricing mode at a time:

• Per cubic yard — order volume (yd³) × your price
• Per cubic meter — order volume (m³) × your price
• Per US short ton — estimated order mass (US short tons) × your price
• Per metric tonne — estimated order mass (tonnes) × your price

CostRafter does not invent market prices. Delivery, labor, tax, and site preparation are excluded. Currency for this version is USD.

Worked Calculation Examples

Examples below were computed with CostRafter’s gravel_materials engine (v1.0.0).

Driveway strip, crushed stone, 10% allowance

Area 20 ft × 10 ft × 3 in, crushed stone default density (1600 kg/m³), waste 10%:

• Base volume: 50 ft³ ≈ 1.8519 yd³ (about 1.4158 m³)
• Order volume with 10% allowance: 2.037 yd³
• Estimated order weight: about 2491.88 kg ≈ 2.4919 metric tonnes ≈ 2.7468 US short tons

Two areas, pea gravel, volume pricing

Drive 12 ft × 10 ft × 4 in plus path 8 m × 1.2 m × 5 cm, pea gravel default, waste 10%, user price $55/yd³:

• Base volume: about 2.1093 yd³; with allowance: 2.3202 yd³
• Estimated material cost: about $127.61

Metric bed, custom density, tonne pricing

Area 5 m × 3 m × 0.1 m, custom density 1500 kg/m³, 0% waste, user price $40/metric tonne:

• Volume: 1.5 m³
• Mass: 2.25 metric tonnes
• Estimated material cost: $90.00

Common Gravel Calculation Mistakes

• Mixing up cubic yards (volume) with tons or tonnes (mass).
• Using a compacted density when ordering loose trucked material, or the reverse.
• Forgetting depth units—inches vs feet changes volume dramatically.
• Treating a planning density as an exact quarry ticket weight.
• Including delivery or labor in a material-only price comparison.

Important Assumptions and Limitations

• Areas are rectangular prisms; irregular shapes need separate takeoffs.
• Densities are loose bulk planning estimates unless you enter a custom value.
• Moisture, compaction, and gradation can change delivered weight for the same volume.
• Allowance is optional purchasing guidance, not a universal requirement.
• Optional cost uses only your price (USD) and excludes delivery, labor, tax, and site preparation.

Confirm final purchase quantities against your supplier’s density and delivery terms.