Aggregate Calculator
Calculate material volume, weight, and coverage. Calculates volume, weight, and bag requirements for gravel, sand, crushed stone, and other aggregates based on…
Calculates volume, weight, and bag requirements for gravel, sand, crushed stone, and other aggregates based on standard bulk densities.
How are Aggregate Quantities Calculated?
Aggregate calculation converts area and depth measurements into volume, weight, and bag counts using material-specific bulk densities. This calculator uses gravel 1850 kg/m³, sand 1600 kg/m³, crushed stone 1600 kg/m³, topsoil 1100 kg/m³, and mulch 400 kg/m³ — enter a custom density if your supplier quotes a different value.
Compaction factor should be considered — loose aggregates compact 10-15% when placed and vibrated. For driveways, pathways, and drainage layers, the recommended depth is typically 50-150mm depending on application and load requirements.
Coverage area calculation helps estimate material needed for landscaping projects. A cubic meter of gravel covers 20 m² at 50mm depth, or 10 m² at 100mm depth. Ordering 5-10% extra accounts for uneven ground, edges, and settling.
Formula: Volume (m³) = Length × Width × Depth Weight (kg) = Volume × Density Weight (tonnes) = Weight / 1000 20kg Bags = Weight / 20 Coverage (m²) = Volume / Depth
Example Calculation
A 10m × 3m driveway with 100mm (0.1m) gravel base. Volume = 10 × 3 × 0.1 = 3.0 m³. Weight = 3.0 × 1850 = 5550 kg = 5.55 tonnes. 20kg bags = 278 bags (rounded up). Coverage area = 10 × 3 = 30 m².
When to Use This Calculator
- Landscapers and contractors ordering gravel, sand, or crushed stone for driveways, pathways, drainage layers, or garden beds
- Homeowners estimating material quantities and costs for DIY landscaping projects before visiting the supply yard
- Civil engineers calculating sub-base material volumes for road construction, parking areas, or building foundations
- Delivery drivers and dispatch teams converting between volume (m³) and weight (tonnes) to plan truck loads for material deliveries
Common Mistakes to Avoid
- Using one density value for all aggregates — bulk densities vary significantly: this calculator assumes gravel 1850 kg/m³, sand 1600 kg/m³, crushed stone 1600 kg/m³, topsoil 1100 kg/m³, mulch 400 kg/m³
- Not accounting for compaction — loose aggregates compact 10-15% when placed and vibrated; order based on the compacted depth plus the compaction factor
- Measuring area accurately but using an unrealistic average depth — uneven ground means some areas need more material; survey depth at multiple points and average
- Ordering in volume when the supplier sells by weight (or vice versa) — always confirm the pricing unit and convert using the correct bulk density for the specific material
How to Interpret Results
- Weight uses the tool's built-in bulk densities — gravel 1850, sand and crushed stone 1600, topsoil 1100, mulch 400 kg/m³; if your supplier quotes a different figure, switch to Custom, since moisture content alone can shift bulk density by 5-15%
- Weight (Tonnes) is the number to give bulk suppliers, who sell by the tonne — the 20 kg and 25 kg bag counts are rounded up to whole bags and only make sense for small orders
- Coverage Area is simply the length × width footprint you entered — use it to confirm the plan area, not to estimate how far a given volume stretches at a different depth
- No compaction allowance is applied — compacted sub-base layers lose roughly 10-15% of their loose thickness, so order against the loose depth needed to achieve the specified compacted depth
- Add 5-10% to the calculated quantity for uneven subgrade, edge losses, and settlement before placing the order
Related Standards & References
- ASTM C29 — Standard Test Method for Bulk Density ("Unit Weight") and Voids in Aggregate
- ASTM C33 — Standard Specification for Concrete Aggregates
- ASTM D1241 — Standard Specification for Materials for Soil-Aggregate Subbase, Base, and Surface Courses
Frequently Asked Questions
How deep should gravel be for a driveway?
Recommended gravel depth: 100-150mm (4-6 inches) for residential driveways, 150-200mm for heavy vehicle access, 50-75mm for garden pathways, and 200-300mm for parking areas. Use a geotextile fabric below gravel on soft ground to prevent sinking.
How much extra material should I order?
Order 5-10% extra for standard rectangular areas. Add 10-15% for irregular shapes with many cuts. Consider compaction factor (10-15% for sub-base layers). It is more cost-effective to have a small surplus than to place a second delivery order.