Concrete Calculator
Concrete projects require accurate volume calculation — too little results in incomplete work, too much means wasted money. This calculator computes exactly how much concrete you need and how many bags to order.
結果
50 zakken
Concrete bags (25kg)
- Volume in cubic feet
- 33.33 ft³
- Volume in cubic yards
- 1.23 yd³
- Volume in cubic meters
- 0.944 m³
How this was calculated
- 1Convert depth to feet4" ÷ 12 = 0.333 ft
- 2Calculate volume in cubic feet10 ft × 10 ft × 0.333 ft = 33.33 ft³
- 3Convert to cubic yards33.33 ft³ ÷ 27 = 1.23 yd³
- 4Calculate concrete bags (25kg each)0.944 m³ × 52 zackar/m³ = 50 zackar
公式
Concrete volume (m³) = Length ft × Width ft × Depth ft ÷ 27 × 0.765. Bags = Volume m³ × 52 (for 25kg bags).
First calculate volume in cubic feet (length × width × depth in feet). Then convert to cubic yards (÷ 27) and then to cubic meters (× 0.765). Finally multiply by 52 because one cubic meter approximately contains 52 bags of 25kg concrete.
ステップ解説
- 1Measure the length and width of the concrete project in feet.
- 2Determine the required depth in inches (typically 4" for driveways, 6" for foundations).
- 3Enter the values and the calculator computes the volume and number of bags.
- 4Order enough bags, plus 1-2 extra for spillage (mixing, shifts, etc.).
計算例
Driveway concrete: 20ft × 10ft × 4 inches
→ 66 cubic feet = 2.44 yd³ = 1.87 m³ ≈ 97 bags
Patio concrete: 15ft × 15ft × 4 inches
→ 75 cubic feet = 2.78 yd³ = 2.12 m³ ≈ 110 bags
Foundation concrete: 30ft × 24ft × 6 inches
→ 360 cubic feet = 13.33 yd³ = 10.20 m³ ≈ 530 bags
Reference table
| Project type | Depth | Notes |
|---|---|---|
| Driveway | 4 inches | Min. 4", better 5-6" for heavy vehicles |
| Patio | 4 inches | 4" standard, deeper for frozen ground areas |
| Foundation | 6-8 inches | Deeper for large structures or soft soil |
| Pad/Post | 12+ inches | Much deeper for foundation stability |
Depths depend on local building codes and soil conditions.
よくある間違い
- Entering depth in centimeters when calculator expects inches — convert to inches first.
- Not accounting for ground prep — soil must be compacted, otherwise concrete can crack.
- Not accounting for bag mixing — ordering bags assumes concrete mix, not powder.
活用シーン
- Budgeting and material planning for large concrete projects — accurate volume means accurate budgeting.
- Delivery coordination — know how many bags you need before you order, prevent emergency deliveries.
- Accurate calculation of labor costs and estimates for contractors.
よくある質問
Can I use pre-mixed concrete instead of bags?
Yes, for large projects (>1 m³) pre-mixed concrete (delivered by truck) is cheaper. For smaller projects bags are more practical.
How long does concrete take to cure?
Concrete reaches full strength in 28 days. You can typically walk on it after 24-48 hours, but don't heavy-load it until fully cured.
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