Gravel & Aggregates Calculator

How to measure

1. Measure the length and width of the driveway, pathway, or French drain trench.
2. Determine required compacted gravel depth (e.g., 5 cm / 2 in for walkways; 10–15 cm / 4–6 in for vehicle driveways).
3. Obtain specific bulk density from your local aggregate quarry (typically 1.6 tonnes/m³ / 1.35 tons/yd³).
4. Add a 10–15% compaction allowance for vibratory mechanical plate compacting.

Input guide

• Enter project length and width in meters or feet.
• Input layer depth in centimeters or inches.
• Set bulk density (standard crushed limestone/granite is 1.6 t/m³).
• Enter price per tonne or ton to budget total aggregate cost.

Formula

The calculator determines volumetric space from length, width, and converted depth.

Volume is adjusted for mechanical compaction settling and multiplied by stone density.

Results output metric tonnes or imperial short tons.

Worked example: Crushed stone driveway sub-base layer

1. A driveway section measuring 10.0 m length by 3.0 m width equals 30.0 m².
2. At a compacted depth of 10 cm (0.10 m), base volume is 3.0 m³.
3. With a 10% compaction factor, adjusted volume is 3.3 m³.
4. Multiplying 3.3 m³ by a density of 1.6 t/m³ gives 5.28 tonnes (rounded to 5.3 tonnes).

At 35 USD per tonne, estimated aggregate cost is 185.50 USD for 5.3 tonnes.

Buying advice

• Install heavy-duty woven geotextile fabric beneath gravel to prevent stones from sinking into subsoil.
• Check supplier delivery truck weight limits (tri-axle dump trucks carry 15–20 tonnes).
• Select angular crushed stone rather than smooth river pebbles for stable, interlocking vehicle driveways.

Common mistakes

• Using loose spread depth instead of final compacted depth.
• Forgetting to contain loose aggregate with durable steel, aluminum, or concrete edging.
• Using fine sand mixes that wash away in heavy drainage zones.
• Not checking for overhead wire clearances prior to dump truck delivery.