🏗️ Concrete Calculator PRO
Volume, rebar, formwork, material breakdown & cost — all in one.
Dimension Diagram — updates as you type
Slab plan view. Length × width gives the area; thickness gives the depth of the pour.
1 Project Type
2 Shape
3 Dimensions
4 Rebar (Optional)
5 Options
Labour Cost
Results
Volume
Bags Needed
Material Breakdown (approximate)
Rebar
Formwork
Cure Time
⚠️ Pre-Export Checklist
- Footings measured on-site
- Sub-grade compacted and level
- Reinforcement placed per structural drawings
- Formwork secured and oiled
- Building permit obtained
- Weather forecast checked (no rain for 24h)
- Pump truck / wheelbarrows arranged
Professional Concrete Estimation Guide
Show formulas, worked examples & pro tips ▼
Formulas
Rectangle = L × W × T
L-Shape = (L₁ × W₁) − (L₂ × W₂) × T
Trapezoid= ((Top + Bottom) ÷ 2) × Length × T
Circle= π × r² × Depth × Quantity
Stairs= Number of steps × (Riser × Tread × Width)
Material Mix (1:2:3 ratio):
Cement = Volume ÷ (1+2+3) × 1.5 (bags per cu ft)
Sand = Volume × (2 ÷ 6) × 1.5 tons per cu yd
Gravel = Volume × (3 ÷ 6) × 1.5 tons per cu yd
Rebar Weight= Bars × Length × Weight per ft (varies by bar size)
Worked Example — 10×10 ft Slab, 4" thick
- Volume: 10 × 10 × (4÷12) = 33.3 cu ft = 1.23 cu yd
- Bags (80 lb): 33.3 ÷ 0.60 = 56 bags → with 10% waste = 62 bags
- Cement: ~62 bags × 94 lb = 2.9 tons cement
- Sand: ~1.1 cu yd = 1.6 tons
- Gravel: ~1.6 cu yd = 2.4 tons
- Water: ~33.3 × 6 gal/cu yd = 25 gallons
- Rebar (#4 @ 12" O.C. both ways): 11 bars × 10 ft = 110 ft = 73.5 lb
Common Mistakes to Avoid
- Forgetting to convert inches to feet (4 in = 0.333 ft, not 4)
- Not adding waste — always 5-15% depending on site conditions
- Using wrong bag yield — 80 lb = 0.6 cu ft, 60 lb = 0.45, 40 lb = 0.30
- Ignoring rebar overlap — add 40× bar diameter for each splice
- Not checking concrete pump accessibility for large pours
- Pouring in direct sunlight without curing compound
Pro Tips
- For pours >1 cu yd, order ready-mix trucks instead of bags
- Use a concrete vibrator to eliminate air pockets
- In hot weather (>90°F), add ice to mix water to slow setting
- Spray curing compound immediately after finishing
- Control joints should be spaced at 24-30× slab thickness
- Order 10% extra — uneven subgrade always uses more concrete
Drag to rotate — Scroll to zoom
相关计算器
Frequently used together on the same project.
Client & Quote (prints on PDF & Excel)
Adjustments (applies to exports)
Contingency is added as a separate line on the exported cost summary. Waste % is printed as an advisory reminder.
Project notes (prints on PDF & Excel)
Result compare (A/B)
| Item | Pinned | Current | Change |
|---|---|---|---|
Saved rates auto-apply from your Price Library. Advanced details stay in your browser — nothing is uploaded except inside your own PDF/Excel exports.
我们的免费在线 混凝土 计算器可以精确计算您的建筑项目所需的材料数量。无论您是需要slabs, footings, and columns的计算器，此工具都可以处理。输入您的项目尺寸即可获得即时结果。
📖 如何使用此 混凝土 计算器
如何使用此 {c} 计算器
📐 理解混凝土公式
基本公式是：体积 = 长度 × 宽度 × 深度。所有尺寸必须使用相同单位。在得到体积后，转换为所需的单位并加上损耗系数。
⚠️ 应避免的常见错误
估算时未将英寸转换为英尺
✓ 确保所有尺寸使用相同单位。
忽略损耗系数
✓ 始终添加5-10%。
材料计算不准确
✓ 请使用我们的计算器获得精确的数量。
💡 专业提示
始终订购超出计算量的材料。
检查当地建筑规范。
提前订购材料。
❓ 常见问题
输入您的项目尺寸，即可获得材料数量和成本估算。
是的，本计算器适用于各种规模的项目。
🏗️ 实际应用
我们的混凝土计算器适用于各种建筑项目。无论是小型修补还是大型施工，此工具都提供准确的估算。
我们的免费混凝土计算器是估算slabs, footings, and columns最准确的在线工具。
✅Method, Sources & Review
Maintained by theBuildingCalc methods desk· Last reviewedSeptember 23, 2026. This calculator implements the standards and references below; every figure can be rechecked against the formulas and worked example on this page.
Results are estimates, not engineering advice. Verify against local codes and licensed professionals for structural, electrical, and gas work. See ourTerms. Spotted an error? Report it— corrections ship with the next review.