TryBuildCalcGSB Quantity Weight Calculator(Granular Sub-Base Weight & Truck Loads)
Calculate GSB weight with compaction.
🕒 Last updated: August 19, 2026
Inputs
ℹ️Auto-filled from aggregate type. Edit it if your supplier provides a tested bulk density.
Dimensions of the Area to be Filled / Covered
Enter the length and width of your site area, and the thickness/depth of the aggregate layer you need.
ℹ️Enter your actual quoted material rate. The calculator does not estimate market price.
16.20 m³
572.10 ft³ • 5.72 brass
GSB (Granular Sub-Base)
30,845 kg
30.85 tonnes
32,387 kg
32.39 tonnes • +5% wastage included
3.2 loads
4 full load(s), based on Standard (10T)
Density Used: 1,700 kg/m³
Moisture Condition: DRY
Aggregate Classification: IS 383:2016 / ASTM C33 / EN 12620
Aggregate Quantity Visualization
GSB (Granular Sub-Base) order quantity with compaction
GSB layers are compacted after placement, so the finished layer volume needs additional loose material ordered up front — this page pre-fills a 12% compaction allowance, a common figure for sub-base planning.
Edit the layer dimensions or compaction percentage above to match your project's road/sub-base design.
- Default density: 1,700 kg/m³, default compaction: 12%.
- Compaction allowance is added on top of the finished-layer volume before converting to weight.
- Useful for road base and plinth sub-base layers.
How Is Aggregate Weight Calculated?
Aggregate weight is calculated by first finding the required volume, then converting that volume into weight using bulk density. The calculator can also add compaction, moisture, wastage, truck load, and cost adjustments so the final result is useful for actual material ordering.
Step 1 — Calculate Finished Volume
Rectangular area: Volume (m³) = Length × Width × Depth
Circular area: Volume (m³) = (π ÷ 4) × Diameter² × Depth
If depth is in mm: Depth (m) = Depth (mm) ÷ 1000
Finished volume is the actual volume of aggregate required in the completed layer. For a rectangular area, if the area is 12 m long, 9 m wide, and 150 mm thick, then depth = 150 ÷ 1000 = 0.15 m. So, volume = 12 × 9 × 0.15 = 16.20 m³. For a circular area — such as a round soak pit or tree ring — with a 3 m diameter and the same 150 mm depth, volume = (π ÷ 4) × 3² × 0.15 = 1.06 m³.
Step 2 — Add Compaction Allowance
Compaction Allowance = Finished Volume × (Compaction % ÷ 100)
Loose Volume = Finished Volume + Compaction Allowance
Aggregates are usually delivered in loose condition. After spreading and compaction, the same material occupies less volume. If the finished volume is 16.20 m³ and compaction is 10%, then compaction allowance = 16.20 × 10% = 1.62 m³. Loose volume = 16.20 + 1.62 = 17.82 m³.
Step 3 — Convert Volume to Weight
Aggregate Weight (kg) = Loose Volume (m³) × Bulk Density (kg/m³)
Bulk density is the weight of aggregate per cubic metre, including the air voids between particles. If loose volume is 17.82 m³ and bulk density is 1,600 kg/m³, then aggregate weight = 17.82 × 1,600 = 28,512 kg, or 28.51 tonnes.
Step 4 — Apply Moisture Adjustment
Moisture Adjusted Weight = Aggregate Weight × Moisture Factor
Wet or saturated aggregate weighs more than dry aggregate. The three selectable moisture factors are Dry (1.00, no adjustment), SSD / Saturated Surface Dry (1.03), and Wet (1.12). If dry weight is 28,512 kg and the aggregate is SSD, adjusted weight = 28,512 × 1.03 = 29,367 kg. For fully wet aggregate, adjusted weight = 28,512 × 1.12 = 31,933 kg. This helps users understand why wet material may show a noticeably higher weight for the same volume.
Step 5 — Add Wastage
Wastage Quantity = Adjusted Weight × (Wastage % ÷ 100)
Final Order Quantity = Adjusted Weight + Wastage Quantity
Wastage covers spillage during unloading, handling loss, spreading loss, and material left on the truck bed. If adjusted weight is 29,938 kg and wastage is 5%, wastage quantity = 29,938 × 5% = 1,497 kg. Final order quantity = 29,938 + 1,497 = 31,435 kg, or 31.44 tonnes.
Step 6 — Convert to Tonnes, Truck Loads, and Cost
Tonnes = Final Weight (kg) ÷ 1000
Truck Loads = Final Weight (kg) ÷ Truck Capacity (kg)
Estimated Cost = Final Weight (tonnes) × Cost per Tonne
Suppliers commonly quote aggregate in tonnes, brass, or truck loads. The calculator converts the final weight into tonnes, estimates the required number of truck loads, and calculates material cost using your entered supplier rate.
Quick Rule of Thumb
- 1 m³ of 20mm aggregate usually weighs around 1.55–1.65 tonnes.
- 1 brass, or 100 cft, of 20mm aggregate usually weighs around 4.4–4.7 tonnes.
- A 10-tonne truck usually carries around 6–6.5 m³ of 20mm aggregate.
Real-World Aggregate Weight Calculation Example
This example uses the active calculator inputs and explains the complete calculation method step by step. Each table shows the formula, values placed into the formula, and the final result.
Input Values Used
| Input | Value | Purpose |
|---|---|---|
| Aggregate type | GSB (Granular Sub-Base) | Used to select practical bulk density |
| Length | 12 m | Site length to be filled or covered |
| Width | 9 m | Site width to be filled or covered |
| Depth / Thickness | 150 mm | Required aggregate layer thickness |
| Bulk density | 1,700 kg/m³ | Converts aggregate volume into weight |
| Compaction factor | 12% | Extra loose material required before compaction |
| Moisture condition | DRY / factor 1 | Adjusts weight for dry, SSD, or wet aggregate |
| Wastage factor | 5% | Allows for unloading, handling, and spreading loss |
| Truck capacity | 10,000 kg | Used to estimate number of truck loads |
Step 1 — Calculate Finished Volume
Finished volume is the actual volume of aggregate required in the completed layer. When dimensions are entered, all units are first converted to metres before multiplying.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Convert length | 12 m converted to metres | 12.000 m |
| Convert width | 9 m converted to metres | 9.000 m |
| Convert depth | 150 mm converted to metres | 0.150 m |
| Finished volume | 12.000 × 9.000 × 0.150 | 16.20 m³ |
| Cubic feet | 16.20 × 35.3147 | 572.10 ft³ |
| Brass | 572.10 ÷ 100 | 5.72 brass |
Step 2 — Add Compaction Allowance
Aggregate is normally supplied loose. After spreading and compaction, it occupies less volume. The compaction allowance estimates the extra loose volume required.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Compaction allowance | 16.20 × (12 ÷ 100) | 1.94 m³ |
| Loose volume | 16.20 + 1.94 | 18.14 m³ |
Step 3 — Convert Loose Volume to Dry Weight
Bulk density converts the loose volume into weight. This calculator uses bulk density because aggregate is purchased, transported, and handled in bulk form.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Dry weight in kg | 18.14 × 1,700 | 30,845 kg |
| Dry weight in tonnes | 30,845 ÷ 1000 | 30.85 tonnes |
Step 4 — Apply Moisture Factor
Wet aggregate weighs more than dry aggregate for the same volume. The moisture factor adjusts the calculated dry weight based on the selected moisture condition.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Moisture adjusted weight | 30,845 × 1 | 30,845 kg |
| Adjusted weight in tonnes | 30,845 ÷ 1000 | 30.85 tonnes |
Step 5 — Add Wastage
Wastage covers spillage during unloading, handling loss, spreading variation, and material left on the vehicle bed.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Wastage quantity | 30,845 × (5 ÷ 100) | 1,542 kg |
| Final order quantity | 30,845 + 1,542 | 32,387 kg |
| Final order quantity in tonnes | 32,387 ÷ 1000 | 32.39 tonnes |
Step 6 — Calculate Truck Loads and Cost
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Truck loads | 32,387 ÷ 10,000 | 3.24 loads |
| Rounded truck loads | Round up to next full load | 4 full load(s) |
Therefore, for this input, the required aggregate quantity is 32,387 kg, or 32.39 tonnes, including compaction, moisture adjustment, and wastage. Based on the selected truck capacity, plan for approximately 4 full truck load(s).
Practical Ordering Note
For site ordering, use the final quantity with wastage, not only the basic dry weight. If your result is close to a truck capacity limit, confirm with the supplier whether they allow partial loads or whether you need to round up to the next full truck.
Calculator Limitations & Assumptions
Bulk density, not particle density: This calculator uses bulk density, which includes air voids between particles. It is appropriate for ordering but not the same as specific gravity used in concrete mix design.
Assumes dry condition by default: Default densities assume dry aggregate. Wet aggregate can weigh 10-25% more for the same volume, so use the moisture condition option when needed.
Density varies by quarry source: Granite, limestone, gravel, and recycled aggregate vary by source, grading, shape, and moisture. Ask your supplier for actual bulk density if accuracy is critical.
Rectangular and circular areas only: This calculator supports rectangular (length × width) and circular (diameter) areas. For irregular L-shaped or multi-part areas, calculate each rectangular or circular sub-area separately and add the volumes together before entering the total in Direct Volume mode.
No structural design output: This calculator estimates quantity only. It does not tell you what aggregate type or size is suitable for structural use.
RCA usage limits apply: Recycled Concrete Aggregate has restricted usage under most national standards — commonly limited to partial replacement (e.g. around 25% for plain concrete and 20% for reinforced concrete up to M25 grade under IS 383:2016; other standards set comparable caps). This calculator does not enforce those limits. Consult your structural engineer before using RCA in concrete work.
Cost excludes delivery and taxes: The estimated material cost is quantity × your entered rate per tonne only — delivery, loading/unloading, and taxes are not included.
Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.