TryBuildCalcVoid Content of Aggregate Calculator(Voids Percentage Formula)
Calculate aggregate void percentage.
🕒 Last updated: August 18, 2026
Inputs
Container Details
IS 2386 (Part III) container guide
Standard containers: 3 litres for fine aggregate (<=4.75mm), 15 litres for aggregate up to 40mm, and 30 litres for aggregate up to 150mm.
Sample Condition
Sample Weights
Derived Properties
ℹ️Required to calculate void content. Use 2.65 for river sand / M sand, 2.68 for granite, or 2.70 for limestone if unknown.
ℹ️Optional. Enter WA% to calculate SSD bulk density.
1,593 kg/m³
1.593 kg/litre - Loose bulk density
Normal-weight concrete reference: 1,200-1,750 kg/m³.
2.68
Used in void calculation (from measurement)
40.5%
Voids (%) = ((Gs - gamma) / Gs) x 100
2,680 kg/m³
Density of individual aggregate particle (no inter-particle voids)
Used in concrete mix design calculations.
Not calculated
Enter water absorption % to calculate SSD density
Test Standard: IS 2386 (Part III) - 1963
Container Volume: 15 litres
Condition: Loose
Net Sample Mass: 23.9 kg
Result accepted
This aggregate meets IS 383:2016 reference checks for normal-weight concrete. Bulk density, specific gravity, and void content are within typical limits.
Aggregate Density Visualizations
Void Content Gauge
Solid aggregate portion is based on specific gravity and bulk density. Void space is the air volume between particles.
How does your aggregate compare?
Aggregate void content formula
Void content indicates the percentage of container volume occupied by air space between particles rather than solid aggregate — this page focuses on that calculation from your bulk density and specific gravity inputs.
Lower void content generally means better particle grading and lower cement paste demand to fill the gaps in a concrete mix.
- Formula: Voids (%) = ((Gs − γ) ÷ Gs) × 100, where γ is bulk density in kg/litre.
- Typical range: 30-45% for well-graded coarse aggregate, higher for single-size material.
- Void content above 45% may indicate poor grading and higher cement paste demand.
How Is Aggregate Density Calculated?
This calculator works in two ways: from your own measured container weights, or from a selected aggregate type reference density. The calculation steps change slightly depending on the input mode.
Aggregate Anatomy: Bulk Density vs Particle Density
Step 1 — Identify Input Mode
From My Measurements: use empty container weight, filled container weight, and container volume
From Aggregate Type: use selected aggregate type and reference bulk density
If you enter your own measurements, the calculator calculates bulk density from the actual sample mass and known container volume. If you select aggregate type, the calculator uses the reference bulk density for that material and condition.
Step 2 — Calculate or Select Bulk Density
From Measurements: Net Mass = Filled Container Weight − Empty Container Weight
From Measurements: Bulk Density (kg/litre) = Net Mass ÷ Container Volume
From Aggregate Type: Bulk Density (kg/m³) = Reference Bulk Density
In measurement mode, density is calculated from the measured sample. In aggregate-type mode, density is selected directly from the reference value for the chosen aggregate and condition.
Step 3 — Convert Bulk Density Units
Bulk Density (kg/m³) = Bulk Density (kg/litre) × 1000
Bulk Density (kg/litre) = Bulk Density (kg/m³) ÷ 1000
Since 1 cubic metre equals 1000 litres, multiplying kg/litre by 1000 gives kg/m³. Dividing kg/m³ by 1000 gives kg/litre. The kg/litre value is used later for void content calculation.
Step 4 — Calculate Particle Density
Particle Density (kg/m³) = Specific Gravity × 1000
Specific gravity compares aggregate particle density with water. A specific gravity of 2.68 means the aggregate particles are 2.68 times denser than water. Since water density is about 1000 kg/m³, particle density = 2.68 × 1000 = 2680 kg/m³.
Step 5 — Calculate Void Content
Void Content (%) = ((Specific Gravity − Bulk Density in kg/litre) ÷ Specific Gravity) × 100
Void content estimates the air gap between aggregate particles. Bulk density is used in kg/litre here because specific gravity is based on water density, and water density is 1 kg/litre.
Step 6 — Calculate SSD Bulk Density (Optional)
SSD Bulk Density (kg/m³) = Dry Bulk Density × (1 + Water Absorption % ÷ 100)
SSD bulk density applies when aggregate is pre-wetted before concrete batching, which is standard practice for mix design per IS 10262:2019. Enter water absorption percentage in the optional field to unlock this result.
Real-World Aggregate Density Calculation Example
This example follows the same calculation flow used by the calculator. In measurement mode, density is calculated from your container weights. In aggregate-type mode, density is selected from the reference value for the chosen material and condition.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Input mode | From my measurements | Decides whether density is calculated from weights or selected from reference data |
| Condition | Loose / uncompacted | Shows whether aggregate is loose or compacted |
| Empty container weight | 3.75 kg | Deducted from filled weight to get aggregate-only mass |
| Filled container weight | 27.65 kg | Includes both container and aggregate |
| Container volume | 15 litres | Known volume occupied by the aggregate sample |
| Specific gravity | 2.68 | Used for particle density and void content calculation |
Step 1 — Calculate Net Aggregate Mass
The filled container weight includes both the container and the aggregate. To get only the aggregate mass, subtract the empty container weight from the filled container weight.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Net aggregate mass | 27.650 kg − 3.750 kg | 23.9 kg |
Step 2 — Calculate Bulk Density
Bulk density means mass per unit volume. Here, the aggregate mass is divided by the container volume because the container volume is the space occupied by the aggregate sample.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Bulk density in kg/litre | 23.9 ÷ 15 | 1.593 kg/litre |
| Bulk density in kg/m³ | 1.593 × 1000 | 1593.33 kg/m³ |
Step 3 — Calculate Particle Density
Specific gravity compares aggregate particle density with water. A specific gravity of 2.68 means the aggregate particles are 2.68 times denser than water. Since water density is about 1000 kg/m³, particle density is calculated as specific gravity × 1000.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Particle density | 2.68 × 1000 | 2680 kg/m³ |
Step 4 — Calculate Void Content
Void content estimates the air gap between aggregate particles. Bulk density is used in kg/litre here so that it is comparable with specific gravity, which is based on water density of 1 kg/litre.
| Calculation | Formula / Substitution | Result |
|---|---|---|
| Void content | ((2.68 − 1.593) ÷ 2.68) × 100 | 40.5% |
| Void content status | Compared with expected practical range | Typical void content |
Therefore, the bulk density is 1593.33 kg/m³, or 1.593 kg/litre. The void content is 40.5%, and the particle density is 2680 kg/m³.
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.