TryBuildCalcAggregate Required for 100 CFT Concrete (100 Cubic Feet Concrete Aggregate Estimate)
Estimate aggregate required for 100 cft concrete.
Use this 100 cft concrete aggregate calculator to estimate coarse aggregate quantity and approximate weight for site material planning.
🕒 Last updated: August 17, 2026
Inputs
Use this calculator when you know concrete volume and mix ratio. If you know the concrete element dimensions, switch to Dimensions mode and the calculator will first calculate concrete volume.
Need aggregate for road base, driveway, GSB, WMM, or area × depth? Use the Aggregate Coverage Calculator or Aggregate Weight Calculator.
ℹ️Selecting aggregate size updates the default ratio, aggregate part, and bulk density.
ℹ️For a 1:2:4 concrete ratio, the aggregate part is 4.
ℹ️Typical value is 1.54 for concrete and PCC aggregate estimation.
ℹ️Used to estimate weight from calculated loose aggregate volume.
Cost
For 2.832 m³ of concrete at a 1:2:4 ratio, you need approximately 2.616 m³ (92.4 cft) of 20mm aggregate — 4.06 tons.
Order Summary — Theoretical vs. Order Quantity
| Theoretical | Order Quantity | |
|---|---|---|
| Volume | 2.492 m³ | 2.616 m³ (92.4 cft) |
| Weight | 3,862 kg | 4,056 kg (4.06 tons) |
Theoretical = before wastage. Order Quantity = after your 5.0% wastage allowance. Round up to a supplier-friendly quantity — approx. 2.7 m³ or 4.1 tons.
Volume & Mix Details
Wet volume: 2.832 m³
Dry volume (×1.54): 4.361 m³
Ratio used: 1:2:4, aggregate part 4
Assumptions Used
Aggregate size: 20mm | Bulk density: 1,550 kg/m³ | Actual weight varies by aggregate size, stone type, moisture, and compaction.
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Aggregate Calculator.
Aggregate for 100 cubic feet of concrete
This page keeps concrete volume in cubic feet for site estimators who measure concrete as 100 cft rather than converting to cubic metres first.
The calculator converts the input internally and reports aggregate volume and weight in both m³ and cft for cross-checking.
- 100 cft ≈ 2.83 m³ — the calculator handles the unit conversion automatically.
- Default aggregate size: 20mm, default ratio: 1:2:4.
- Outputs include m³, cft, kg, and tons, matching however your supplier quotes.
Step-by-step aggregate quantity calculation method
Aggregate quantity calculation starts with the required wet concrete volume. In Direct Volume mode, you enter that concrete volume directly. In Dimensions mode, the calculator first converts length, width, and depth/thickness into concrete volume. The calculator then converts wet volume into dry material volume, applies the selected mix ratio, calculates the aggregate share, and converts loose aggregate volume into approximate weight using bulk density.
For road base, driveway layers, GSB, WMM, or area × depth aggregate-only work, use the Aggregate Coverage Calculator or Aggregate Weight Calculator. This calculator is for concrete mix-ratio aggregate estimation.
Step 1 - Determine required concrete volume
Concrete volume is the finished wet concrete volume required for slabs, beams, columns, PCC, foundations, or other construction works. Enter it directly, or calculate it from dimensions.
Direct Volume Mode: Wet Volume = Entered Concrete Volume
Dimensions Mode: Wet Volume = Length × Width × Depth / Thickness
Step 2 - Convert wet volume to dry volume
Dry volume factor accounts for voids between aggregate particles, sand bulking, compaction, and practical site handling losses. For concrete and PCC estimation, a dry volume factor of 1.54 is commonly used.
Step 3 - Calculate aggregate share from mix ratio
The aggregate ratio part is divided by the total mix ratio parts to calculate the loose aggregate volume required for the selected concrete mix.
Step 4 - Convert aggregate volume to approximate weight
Bulk density converts loose aggregate volume into approximate aggregate weight. The default density changes automatically when you select 10mm, 20mm, or 40mm aggregate, and it can be adjusted for local material conditions.
Step 5 - Apply wastage allowance
Wastage allowance accounts for practical site losses during transport, unloading, storage, handling, and placement.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Concrete volume | 100 ft³ (2.832 m³) | Sets the wet concrete volume to convert |
| Mix ratio / aggregate part | 1:2:4, part 4, ×1.54 | Splits dry volume into the aggregate share |
| Density / wastage | 1,550 kg/m³, 5% wastage | Converts volume to weight and adds a buffer for site losses |
Step 1 — Volume
| Calculation | Substitution | Result |
|---|---|---|
| Wet volume | 100 ft³ (2.832 m³) | 2.832 m³ |
| Dry volume | 2.832 × 1.54 | 4.361 m³ |
Step 2 — Aggregate Quantity
| Calculation | Substitution | Result |
|---|---|---|
| Aggregate volume (theoretical) | 4 / 7 × 4.361 | 2.492 m³ |
| Aggregate weight (theoretical) | 2.492 × 1,550 | 3,862 kg |
| With 5% wastage | 2.492 × 1.05 | 2.616 m³ (4.06 tons) |
Therefore, plan for approximately 2.62 m³ (92.4 cft) — 4.06 tons — of 20mm aggregate for this pour.
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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.