Estimate concrete volume, bag quantities, waste allowance, and project cost for slabs, walls, footings, columns, and stairs.
concrete calculator helps you estimate the amount of concrete required for slabs, footings, walls, columns, stairs, patios, driveways, and other construction projects.
Enter your project measurements, select a waste allowance, and the calculator will convert the result into cubic feet, cubic yards, and cubic metres. It can also estimate the number of concrete bags required and the approximate material cost.
Accurate concrete estimates can help you avoid material shortages, reduce unnecessary waste, control project costs, and plan your concrete pour with greater confidence.
Select whether you are calculating concrete for a slab, wall, footing, round column, or staircase.
Enter the required length, width, height, thickness, diameter, quantity, or number of steps for your selected project.
Choose a waste allowance and bag size to receive instant estimates for total concrete volume, bag quantity, and material cost.
Estimate concrete for patios, driveways, sidewalks, shed bases, garage floors, and other flat surfaces.
Calculate concrete volume for continuous footings, foundations, piers, and structural bases.
Estimate concrete for walls, retaining structures, round columns, posts, and vertical supports.
Calculate concrete requirements for solid stairs, steps, curbs, and similar shaped projects.
| Bag Size | Weight | Approximate Yield | Cubic Yards (Approx.) |
|---|---|---|---|
| Small Bag | 40 lb | 0.30 ft³ | 0.011 yd³ |
| Standard Bag | 60 lb | 0.45 ft³ | 0.017 yd³ |
| Large Bag | 80 lb | 0.60 ft³ | 0.022 yd³ |
Concrete bag yields are approximate. Always check the manufacturer’s stated coverage and mixing instructions before purchasing materials.
Step 1 — Thickness ko feet mein badlo: 4 inches ÷ 12 = 0.333 ft.
Step 2 — Cubic feet mein volume: 10 × 10 × 0.333 = 33.3 cu ft.
Step 3 — Cubic yards mein badlo (ready-mix yard ke hisaab se bikta hai): 33.3 ÷ 27 = 1.23 cubic yards.
Step 4 — Waste margin add karo: spillage aur uneven subgrade 5–10% kha jata hai. 1.23 × 1.1 ≈ 1.35 cubic yards → safe rehne ke liye 1.5 cubic yards order karo.
Bags mein: 80 lb ka ek bag taqreeban 0.6 cubic feet deta hai. 33.3 ÷ 0.6 ≈ 56 bags. ~30 bags se zyada kaam ho to ready-mix delivery aam tor par sasti parti hai.
| Slab size | Cubic yards | 80 lb bags (approx) |
|---|---|---|
| 8 × 8 ft | 0.79 | 36 |
| 10 × 10 ft | 1.23 | 56 |
| 12 × 12 ft | 1.78 | 80 |
| 16 × 16 ft | 3.16 | 143 |
Multiply the slab’s length by its width and thickness. Make sure all measurements use compatible units. If thickness is entered in inches, divide it by 12 to convert it to feet. Divide the resulting cubic feet by 27 to calculate cubic yards.
Adding 5% to 10% is suitable for many projects. A 10% waste allowance is commonly used to cover uneven ground, spillage, measurement differences, and minor changes in depth. Complex projects may require a larger allowance.
An 80-lb bag typically produces approximately 0.60 cubic feet of concrete. Based on that approximate yield, one cubic yard requires around 45 bags. Always verify the actual yield stated by the manufacturer.
Yes. Select the appropriate project type and enter the requested measurements. For round columns, volume is calculated using the column diameter, height, and quantity.
Concrete bags can be practical for small repairs and smaller pours. Ready-mix delivery may be more efficient for larger projects. Compare the required bag quantity, labour, equipment, delivery charges, and site access before deciding.
The calculator provides an estimate based on your measurements and selected waste allowance. Actual concrete requirements can vary because of uneven excavation, ground conditions, form movement, product yield, and measurement differences.
No. Calculations are performed directly in your browser and are not uploaded to our servers. Your entered values may reset when you refresh or leave the page.
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