Cement & Mortar Calculator
Calculate the exact number of cement bags and sand volume required for your concrete or mortar mix.
Cement Calculator
Concrete Details
Estimated Quantities
How to Use This Formula
The Cement Calculator converts wet volume into dry volume using standard industry multipliers, ensuring you order exactly the right amount of raw materials.
- Select the type of mix (Concrete or Mortar).
- Choose your preferred mix grade (e.g., M20 which is 1:1.5:3).
- Enter the total wet volume in cubic feet or cubic meters.
- The tool automatically applies the 1.54x (Concrete) or 1.33x (Mortar) dry volume factor.
Accurate Cement & Sand Mix Calculation
Cement and mortar are the binding agents of any strong structure. Use our cement mix calculator to estimate the exact number of cement bags and sand volume needed for concrete slabs, plastering, or brickwork based on your desired mix ratio.
Frequently Asked Questions
What is a cement bag calculator and how does it work?
A cement bag calculator determines the exact number of 50 kg cement bags, sand volume (cu.ft), and coarse aggregate (ballast) needed for concrete slabs, beams, columns, or mortar plastering. It converts wet volume into dry volume using standard engineering shrinkage factors (1.54 for concrete, 1.33 for mortar) and splits quantities according to your mix ratio.
What is a concrete mix ratio?
A concrete mix ratio is the proportion of Cement : Sand (Fine Aggregate) : Ballast/Gravel (Coarse Aggregate) by volume. Common standard grades under IS 456 include M10 (1:3:6), M15 (1:2:4), M20 (1:1.5:3 for standard RCC structural elements), and M25 (1:1:2 for heavy-duty columns and footings).
What is a good mix ratio for a concrete column and slab?
For residential RCC columns, beams, and roof slabs, M20 grade (1 : 1.5 : 3) is the standard recommended mix ratio as per IS 456:2000. For heavily loaded ground-floor columns or multi-storey buildings (G+2 and above), M25 grade (1 : 1 : 2) is recommended for higher compressive strength.
How much ballast (coarse aggregate), sand, and cement do I need for concrete?
For 100 cubic feet of wet M20 concrete (1:1.5:3), applying the 1.54 dry factor yields 154 cu.ft of dry materials. This requires approximately 8.2 bags of cement (50kg each), 15.4 cu.ft of sand / M-sand, and 30.8 cu.ft of ballast (20mm coarse aggregate).
Why do we multiply wet concrete volume by 1.54 for dry volume?
When dry cement, fine sand, and water are mixed, smaller particles settle into voids between coarse aggregate stones, causing dry volume to shrink by ~30–35% during wet compaction. To achieve 1 m³ of compacted wet concrete, you need 1.54 m³ of dry materials (a 54% dry volume factor).
How many kilograms and cubic feet are in 1 standard bag of cement?
In India and standard civil engineering practice, 1 commercial bag of cement weighs exactly 50 kg (110.23 lbs) and has a loose volume of 1.226 cubic feet (0.0347 cubic meters or 34.7 liters).