Chip Seal Aggregate Calculator

Area is converted to m² internally.

SpreadRate is converted to kg/m² internally.

BulkDensity is converted to kg/m³ internally.

Suggested rates and densities depend on gradation, binder, and surface condition.

1. Choose your unit system and enter the project area.
2. Select an area unit that matches your measurement source.
3. Pick the nominal chip size to load typical starting values.
4. Enter the spread rate from your specification or trial section.
5. Enter bulk density from supplier data, or measured loose density.
6. Add a waste factor to cover handling and field variability.
7. Enter truck capacity to estimate delivery counts.
8. Press Submit, then download CSV or PDF for your records.

Chip seals are a cost-effective surface treatment that restores skid resistance and seals small cracks, but the performance depends heavily on getting aggregate quantity right. Under-ordering leads to thin cover, early raveling, and exposed binder. Over-ordering increases sweeping time, creates loose stone hazards, and wastes money. This calculator provides a practical, field-ready estimate by combining project area, target spread rate, bulk density, and an allowance for losses.

Start with your specification or a calibrated trial strip. Spread rate is typically expressed as mass per area and varies with aggregate gradation, chip shape, and surface texture. Cleaner, angular aggregate tends to interlock and may be placed at a rate that achieves one-stone thickness after rolling. Softer substrates or rough textures can require additional stone to achieve full cover, while very smooth surfaces may require less to avoid excess loose chips.

Bulk density matters because suppliers often sell by mass, while stockpiles and truck boxes are governed by volume. Moisture, fines content, and particle packing can change loose density. If possible, use supplier ticket density or measure a representative loose unit weight on site. Add a waste factor to cover material loss from wind, spillage at the gate, variable brooming requirements, and segregation during hauling and spreading.

Delivery planning is also important. Estimating truckloads helps schedule haul cycles so the spreader stays fed without creating large stockpiles that degrade quality. When multiple lifts or split applications are used, calculate each pass separately, then combine totals. Always confirm that your truck capacity uses the same ton definition as your supplier and your local practice.

Worked example:

• Area: 5,000 m²
• Chip size: 10 mm
• Spread rate: 12 kg/m²
• Waste: 5%
• Bulk density: 1,600 kg/m³

Total mass = 5,000 × 12 × 1.05 = 63,000 kg (63.0 tonnes). Volume = 63,000 ÷ 1,600 = 39.38 m³. With 18-tonne trucks, plan about 3.50 truckloads and round up for logistics.

1) What spread rate should I use?

Use your project specification or a trial strip. Typical ranges vary by chip size, gradation, and surface texture. Calibrate to achieve one-stone thickness after rolling and initial sweeping.

2) Why does bulk density affect my estimate?

Bulk density converts between mass and volume. Supplier tickets may be by mass, while stockpile space and truck boxes are limited by volume, so density is essential for realistic logistics.

3) How do I choose a waste factor?

Start with 3–8% for controlled operations, then increase for windy conditions, long hauls, poor access, or heavy brooming. Track actual usage and refine the factor for future work.

4) Should I calculate each lane separately?

Yes when widths, textures, or chip sizes change. Separate calculations improve ordering accuracy and help schedule deliveries, especially for staged paving, intersections, shoulders, or split applications.

5) Can I use this for double chip seal?

Yes. Run the calculator for each layer with its own chip size, rate, density, and waste. Add the two totals to obtain combined mass, volume, and trucking requirements.

6) How accurate are the default values?

Defaults are practical starting points only. Local aggregate source, moisture, gradation, and field equipment can shift required rates. Always confirm with specs, tickets, or measured field data.

7) Why do my truckloads show a fraction?

Fractions represent the calculated requirement. For purchasing and scheduling, round up to the next whole load, then plan where to place any surplus stone to avoid waste.