TryBuildCalcLean Concrete Calculator Lean concrete (1:4:8) estimator
Calculate PCC cement, sand, and aggregate instantly.
🕒 Last updated: August 13, 2026
PCC Dimensions
ℹ️Typical: 75-100 mm (foundation blinding), 100-125 mm (flooring / floor base)
Common PCC thickness:
Cost
For a 12.00 m² footprint, you need approximately 1.26 m³ (44.5 cft) of PCC concrete — 4.3 cement bags.
PCC Concrete
Wet volume (before wastage): 1.200 m³
Dry volume: 1.848 m³
Final quantity (with wastage): 1.26 m³ (44.5 cft)
Materials
Cement: 4.3 bags (215 kg)
Sand: 0.60 m³ (21.1 cft)
Aggregate: 1.19 m³ (42.2 cft)
Assumptions Used
Dry volume factor: 1.54 | Cement bag: 50 kg / 0.0347 m³ | PCC is non-reinforced — no steel, and no shuttering (cast directly against the excavation or a prepared subgrade, not panel formwork).
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete PCC Calculator.
Lean concrete (1:4:8) quantity estimate
"Lean concrete" refers to a PCC mix with a lower cement content relative to aggregate — this page is pre-selected to the 1:4:8 ratio, the leanest of the three standard PCC mixes, commonly used for levelling courses where strength requirements are minimal.
Edit the dimensions above and the cement, sand, and aggregate breakdown updates from the active values — this uses the same calculation engine as the main PCC calculator.
- 1:4:8 is the leanest standard PCC mix — lower cement content than 1:3:6 or 1:2:4.
- Commonly used for levelling courses and blinding where load requirements are minimal.
- Lower cement content means lower cost per cubic metre, but confirm it's adequate for your specific application.
How Is PCC Quantity Calculated?
PCC quantity is calculated from wet concrete volume, a dry-volume correction factor, and cement-sand-aggregate mix ratio distribution, then an optional cost estimate on top.
Step 1 — PCC Volume
Wet Volume = Length × Width × Thickness
Dry Volume = Wet Volume × 1.54
Dry volume accounts for the voids between aggregate particles that disappear once the concrete is mixed and compacted. The dry volume is split into cement, sand, and aggregate using the selected mix ratio, and wastage is applied once to the final quantities.
Step 2 — Cement Bags
Cement Volume = Dry Volume × (Cement Ratio Part ÷ Total Ratio Parts)
Cement Bags = Cement Volume ÷ 0.0347 m³/bag (50 kg bags)
Sand and aggregate are split the same way, using their own ratio parts. One standard cement bag (50 kg) occupies approximately 0.0347 m³.
Step 3 — Final Quantity with Wastage
Final Wet Volume = Wet Volume × (1 + Wastage %)
This final wet volume (and the wastage-adjusted cement/sand/aggregate figures) is the practical quantity to order or batch on site — shown separately from the theoretical pre-wastage volume.
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 |
|---|---|---|
| Length × width × thickness | 4m × 3m × 100mm | Sets the wet concrete volume |
| Mix ratio / wastage | 1:4:8, 5% wastage | Splits dry volume into cement/sand/aggregate and adds a buffer for site losses |
Step 1 — Volume
| Calculation | Substitution | Result |
|---|---|---|
| Wet volume | 4m × 3m × 100mm | 1.200 m³ |
| Dry volume | 1.200 × 1.54 | 1.848 m³ |
| With 5% wastage | 1.200 × 1.05 | 1.260 m³ (44.5 cft) |
Step 2 — Materials
| Material | Quantity |
|---|---|
| Cement | 4.3 bags (215 kg) |
| Sand | 0.60 m³ (21.1 cft) |
| Aggregate | 1.19 m³ (42.2 cft) |
Therefore, approximately 1.26 m³ (44.5 cft) of PCC concrete should be ordered or batched for this layer, needing 4.3 cement bags, while sand and aggregate are estimated separately for site mixing.
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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.