Cement Calculator
Estimate the number of cement bags needed for your concrete or mortar mix.
Assumptions
Standard cement bag = 50 kg. Mix ratio affects cement quantity. Add wastage allowance.
Cement Required
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How to use the Cement Calculator
- Enter the concrete volume in cubic metres (use the concrete calculator if needed).
- Select the mix ratio — cement : sand : aggregate.
- Click Calculate to see cement bags (50 kg), sand and aggregate quantities.
- Order a little extra to allow for wastage.
Formula used
Dry volume = wet volume × 1.54
Cement = dry volume × (cement part ÷ sum of parts) ÷ 0.035 bags
Cement = dry volume × (cement part ÷ sum of parts) ÷ 0.035 bags
The 1.54 factor accounts for voids and bulking of dry materials. One 50 kg bag of cement occupies about 0.035 m³.
Worked example
1 m³ of concrete
Mix 1:1.5:3 (about M20): 8 bags (400 kg) cement, 0.42 m³ sand, 0.84 m³ aggregate
Mix 1:2:4 (about M15): 7 bags (350 kg) cement, 0.44 m³ sand, 0.88 m³ aggregate
Which mix ratio should I use?
| Ratio | Approx. grade | Typical use |
|---|---|---|
| 1:3:6 | M10 | Mass concrete, levelling |
| 1:2:4 | M15 | PCC, floors, non-structural |
| 1:1.5:3 | M20 | Slabs, beams, columns (houses) |
| 1:1:2 | M25 | Higher-strength members |
Tips for accurate results
- Store cement bags off the floor and use them within about 3 months.
- Sand and aggregate are often sold in cubic feet: 1 m³ = 35.31 ft³.
- For structural work, follow your engineer's mix design.
Frequently Asked Questions
Roughly 8 bags with a nominal 1:1.5:3 mix.
Dry materials shrink when mixed with water because sand fills gaps between stones; 1.54 corrects for this.
Usually a water-cement ratio of about 0.45–0.5 by weight for nominal mixes.
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Content reviewed by Vinod, Easy Smart Calculator · Last updated October 2026