Subbase Volume Calculator

Plan subbase volume, weight, and deliveries accurately now. Include waste, moisture, and compaction adjustments easily. Download reports, reduce rework, and order materials confidently always.

Conversions are applied automatically.
Choose the shape to calculate area.
Metric: enter millimeters.
Metric: meters.
Metric: meters.
Metric: meters.
Metric: square meters.
Covers trimming, spillage, and handling loss.
Adds extra loose volume to reach compacted thickness.
Metric: kg/m³.
Metric: m³ per load.
Results appear above after submit.

Example data table

Project Shape Dimensions Thickness Waste Compaction Loose volume
Driveway pad Rectangle 12 m × 8 m 150 mm 5% 10% 15.84 m³
Round footing zone Circle Radius 4 m 200 mm 7% 12% 11.30 m³
Walkway base Area 55 m² 100 mm 4% 8% 6.18 m³

Formula used

  • Rectangle area: A = L × W
  • Circle area: A = π × R²
  • Compacted volume: Vc = A × T
  • Loose volume with allowances: Vl = Vc × (1 + C/100) × (1 + W/100)
  • Mass (optional): M = Vl × ρ
  • Truckloads (optional): Loads = V / Capacity
Where A is area, L is length, W is width, R is radius, T is thickness, C is compaction allowance, W is waste allowance, and ρ is density.

How to use this calculator

  1. Select a unit system that matches your measurements.
  2. Choose an area method and enter the required dimensions.
  3. Enter the subbase thickness for your design section.
  4. Add waste and compaction allowances to reduce shortages.
  5. Optionally add density to estimate total material weight.
  6. Optionally add truck capacity to estimate delivery loads.
  7. Press Submit to view results above the form.
  8. Use the download buttons to export the result sheet.

Scope and inputs used on site

Accurate subbase takeoff starts with footprint and compacted thickness. Choose rectangle, circle, or enter measured area from drawings or takeoff software. Metric uses meters and millimeters; imperial uses feet and inches. The calculator converts everything internally, so results stay consistent. For irregular shapes, sum areas by zones and run separate entries when thickness changes across the project. Include planned shoulder extensions, overbreak, and tie-ins to existing pavement when defining the footprint for accurate ordering.

Area and thickness conversion logic

Rectangles use A = L × W and circles use A = π × R². Imperial dimensions convert to meters, while square feet convert to square meters. Thickness converts from inches or millimeters to meters. This single unit base prevents hidden errors during estimation and reporting. Keep your selected unit system aligned with field measurements to avoid double conversions.

Allowances for compaction and waste

Material is delivered loose but must meet a compacted design. The calculator first computes compacted volume Vc = A × T, then applies compaction and waste factors. Loose volume is V = Vc × (1 + C/100) × (1 + W/100). Use higher compaction allowance for aggregates that densify strongly, and higher waste where trimming and edge losses are expected.

Weight and delivery planning outputs

When density is provided, the tool estimates mass for quotation checks and hauling limits. Enter density from supplier data or prior tests, matching the delivered condition. Optional truck capacity converts volume to estimated loads, supporting delivery schedules and stockpile planning. Compare loads with site access, tipping locations, and placement sequence to reduce rehandling and delays.

Practical checks before purchasing

Confirm subgrade elevations, crossfall, and boundaries match the measured area. Separate calculations for staged lifts or different thickness zones, then combine totals for procurement. Verify you are estimating the correct layer, especially where base course differs from subbase. Export the report and attach it to the purchase request so assumptions, allowances, and quantities remain traceable for review.

FAQs

Should I enter compacted or loose thickness?

Enter the compacted design thickness. The calculator adds compaction allowance to estimate the loose quantity you must order and deliver.

What compaction allowance should I use?

Use your project specification or historical data. Typical allowances range from 5% to 15%, depending on aggregate gradation, moisture control, and compaction equipment.

How do I handle multiple thickness zones?

Run the calculator once for each zone or lift using its own area and thickness. Then add the loose volumes together for procurement.

Where can I get a realistic density value?

Use supplier submittals, quarry data, or recent lab results. Density should represent the delivered material condition you are paying for.

Why do the results show cubic meters and cubic yards?

The tool calculates in a consistent base unit and then shows common conversions. This helps communication between design teams, suppliers, and crews using different unit systems.

Can I estimate truckloads accurately with this?

Yes, if you enter a realistic per-load capacity for your trucks. Always check local haul limits, material bulking, and site access constraints before final scheduling.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.