Plan every pour confidently with smart waste factors and unit checks built-in. See order volume, extra margin, costs, and truckloads instantly after calculation below.
| Scenario | Planned Volume (m³) | Waste Factor (%) | Order Volume (m³) | Truck Capacity (m³) | Trucks |
|---|---|---|---|---|---|
| House slab plus small footing | 18.500 | 12.00 | 20.720 | 8.000 | 3 |
| Trench pour with irregular sides | 9.200 | 15.50 | 10.626 | 6.000 | 2 |
| Column set with tight forms | 4.750 | 8.00 | 5.130 | 8.000 | 1 |
Concrete is ordered once, but placed in many uncontrolled steps. Small losses from pump priming, chute washout, and wheelbarrow handling compound quickly. A managed waste factor protects schedule continuity, prevents cold joints, and reduces emergency short-load charges on active pours.
Many residential slabs plan 5 to 10 percent waste, while complex forming, heavy reinforcement, or limited access can push allowances to 12 to 18 percent. Trench pours and irregular excavation profiles commonly require additional margin. Always review previous project tickets to calibrate your baseline.
Dimensional tolerances, subgrade settlement, and form bulging change net volume. Over-excavation, rock pockets, and edge thickening add hidden demand. Hot weather can increase finishing rework, and inexperienced crews may overfill around embeds and sleeves.
Itemized mode sums L times W times D for each element and multiplies by quantity. Use thickness in meters or feet consistently, and separate components such as grade beams, pads, and stair landings. Itemization improves visibility and supports phased ordering for larger sites.
Increase spillage allowances when access is narrow, elevations change, or transfers occur between pumps and buckets. Add overbreak for trenches in loose soil or when excavation is manual. Reserve rework allowance for exposed edges, broom finishes, or architectural pours.
Continuous placement is the goal. By pairing order volume with truck capacity, the calculator estimates deliveries and highlights rounding choices. Rounding up reduces stoppage risk, while nearest rounding may fit tight budgets when onsite contingency is available.
Entering unit price converts volume into cost impact. The waste cost estimate shows how much budget is tied to contingency, helping teams decide whether better formwork, tighter excavation control, or improved handling can reduce allowances without compromising quality.
Confirm units on supplier quotes, keep a log of returned concrete, and note reasons for overages. Review waste factors after each pour and update templates for similar work. With measured feedback, this calculator becomes a forecasting tool, not a guess. Track tickets compare planned versus delivered and refine allowances for each crew mix and placement method over time to improve accuracy Track tickets compare planned versus delivered and refine allowances for each crew mix and placement method over time to improve accuracy Track tickets compare planned versus delivered and refine allowances for each crew mix and placement method over time to improve accuracy Track tickets compare planned versus delivered and refine allowances for each crew mix and placement method over time to improve accuracy Track.
Start with 8 to 12 percent for typical slabs. Increase for difficult access, transfers, irregular excavation, or detailed finishes. Reduce only when past tickets show consistent performance.
No. Use it to add controlled contingency to a takeoff. Itemized mode can help validate totals, but drawings, thickness notes, and site measurements remain essential.
Truck capacity and order volume must share the same unit. If capacity stays in one system while volume changes, the estimate shifts. Always match supplier tickets.
Round up for continuous pours or when short loads are expensive. Nearest rounding can work for small pours with onsite contingency, but it increases shortage risk.
Log returned volume and the reason, then reduce future allowances only when causes are addressed. Returns may still be cheaper than downtime on critical placements.
Yes. Add pump-related loss into spillage and handling. For long hose runs or frequent line cleaning, increase that component to reflect real ticket history.
Use itemized mode and separate elements with different thicknesses. Add conservative overbreak for trenches and edges, then refine after the first similar pour is completed.
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.