Calculate pad volume, concrete bags, cost, and waste. Adjust depth, density, reinforcement, and unit settings. Build reliable concrete plans using clear exportable results.
| Shape | Length / Radius | Width | Thickness | Waste | Net Volume | Volume with Waste |
|---|---|---|---|---|---|---|
| Rectangle | 12 ft | 10 ft | 4 in | 8% | 1.13 m³ | 1.22 m³ |
| Rectangle | 16 ft | 14 ft | 5 in | 10% | 2.64 m³ | 2.90 m³ |
| Circle | Radius 6 ft | — | 4 in | 7% | 1.19 m³ | 1.28 m³ |
| Circle | Radius 8 ft | — | 6 in | 10% | 3.56 m³ | 3.91 m³ |
Example values are illustrative. Actual mix yield, compaction, and site waste may change material requirements.
Rectangle area: Area = Length × Width
Circle area: Area = π × Radius²
Concrete volume: Volume = Area × Thickness
Waste-adjusted volume: Adjusted Volume = Volume × (1 + Waste% / 100)
Bag count: Bags Needed = Ceiling(Adjusted Volume ÷ Yield per Bag)
Estimated cost: Total Cost = Adjusted Volume × Cost per Cubic Meter
Mesh estimate: Mesh Area = Pad Area × (1 + Overlap% / 100)
Rebar estimate: Rebar Length is approximated from spacing in two directions, then increased by the extra allowance percentage.
A waste allowance of 5% to 10% is common for small pads. Use more when the subgrade is rough, forms are uneven, or access is difficult. Local contractor practice and supplier minimums can also affect your final order.
Suppliers use different ordering units. Cubic meters are common in many countries, while cubic yards are common in others. Showing both helps you compare quotes, convert quickly, and avoid ordering mistakes.
Yes. The calculator works for most flat concrete pads when you know the plan dimensions and thickness. It is useful for patios, equipment pads, shed slabs, AC bases, and small walkways.
Yes. Different bag weights and brands produce different yields. Always confirm the yield printed by the manufacturer. Entering the actual yield gives better results than assuming every bag performs the same.
Mesh is often used for light-duty slabs and crack control. Rebar is often chosen for heavier loads, edge strengthening, or structural requirements. Final reinforcement selection should follow project drawings or engineering guidance.
Not always. Some pads have thickened edges, slopes, or step-down areas. This calculator assumes a uniform thickness. For variable sections, divide the project into smaller parts and total the volumes.
No. It estimates quantity, bag count, reinforcement coverage, and cost. Structural design depends on soil bearing, loading, reinforcement layout, concrete strength, and code requirements that should be checked separately.
You cannot buy a fraction of a bag in most cases. Rounding up helps ensure you have enough material to complete the pour, especially after accounting for waste, mixing losses, and finishing adjustments.
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.