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Concrete Calculator
Concrete Dimensions
Concrete Grade
Volume Calculations
Material Requirements
Material Breakdown
How We Calculate Concrete Requirements
Step 1: Volume Calculation
We calculate the concrete volume by multiplying Length × Width × Thickness. Thickness is converted from inches to feet (÷ 12), then converted to cubic meters and yards.
Step 2: Concrete Grade & Mix Ratio
Based on M20 grade concrete, we use the mix ratio 1:1.5:3 (Cement:Sand:Aggregate). Different grades have different strength requirements and applications.
Step 3: Dry Volume Adjustment
We add 54% to the wet volume to get the dry volume of materials needed. This accounts for voids and compaction in the concrete mixture.
Step 4: Material Distribution
Based on the 1:1.5:3 ratio, we distribute the dry volume proportionally among cement, sand, and aggregate:
- Cement: 8 bags (380.58 kg)
- Sand: 14 cubic feet
- Aggregate: 28 cubic feet
- Water: 171.26 liters (0.45 water-cement ratio)
Key Assumptions
- • Cement density: 1440 kg/m³
- • Water-cement ratio: 0.45
- • Dry volume factor: 1.54 (54% increase)
- • Standard cement bag: 50 kg
- • Cost estimates: Cement ₹400/bag, Sand ₹50/cft, Aggregate ₹60/cft
Pro Tips
Grade Selection:
- • M10/M15 - Plain concrete, foundations
- • M20 - Standard RCC work, slabs
- • M25 - Columns, heavy load structures
- • M30 - Prestressed concrete work
Best Practices:
- • Use clean water for mixing
- • Proper curing for 28 days
- • Adequate compaction during pouring
- • Order 5-10% extra concrete
About This Concrete Calculator
This calculator helps homeowners, contractors, and site engineers estimate cement, sand, aggregate, and water requirements for RCC slabs, footings, and other concrete work. Choose a concrete grade from M10 to M30, enter your dimensions, and get an instant material and cost estimate based on standard Indian mix ratios.
Concrete Calculator FAQs
What do M10, M15, M20, M25, and M30 mean?
These are concrete grade designations indicating characteristic compressive strength in MPa (e.g., M20 = 20 MPa) and correspond to standard mix ratios like 1:1.5:3 for M20.
Which grade should I use for my project?
M10/M15 suit plain concrete and leveling work, M20 is standard for RCC slabs and beams, M25 for columns, and M30 for prestressed concrete elements.
How is the cement quantity determined from the grade?
Each grade has a fixed cement:sand:aggregate ratio; the calculator applies a 1.54x dry volume factor, then splits the dry volume proportionally across the ratio's parts to get cement, sand, and aggregate quantities.
What water-cement ratio does this calculator assume?
It uses a 0.45 water-cement ratio by weight, a commonly recommended value for workable, durable concrete.
Is the cost estimate accurate for my city?
The cost estimate uses average national rates (cement ₹400/bag, sand ₹50/cft, aggregate ₹60/cft) — actual local prices may vary, so treat it as a ballpark figure.
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