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Concrete Calculator
Estimate concrete volume for a slab, path or footing.
Volume = length × width × depth. Add 5–10% for compaction and spillage. The bag count uses roughly 0.015 m³ of concrete per 25 kg bag.
How it works
Volume = length × width × depth. Add 5–10% for compaction and spillage. The bag count uses roughly 0.015 m³ of concrete per 25 kg bag.
Worked example
A 4 m × 3 m slab at 15 cm deep = 4×3×0.15 = 1.8 m³, +5% ≈ 1.89 m³ ≈ 126 bags of 25 kg.
Recommendations
- Order 5–10% extra for uneven ground and spillage
- For footings, add reinforcement steel
- Smaller jobs: use premix bags rather than a truck
Tips & advice
- Compact the subgrade before pouring
- Pour on a dry day to avoid washing out the mix
- Cure the slab by keeping it moist for 7 days
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Concrete Calculator
Estimate concrete volume for a slab, path or footing.
Use the calculatorInvoice Generator FAQs
Yes, all 20 home calculators are 100% free, private and run entirely in your browser. No account needed.
They use standard industry formulas. Always round up for materials and confirm with a professional for structural work.
The calculators use metric units (meters, liters, m³). Convert imperial measurements beforehand if needed.
No. Calculations happen instantly in your browser and nothing is sent to any server.
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