Cement Calculator: How Many Bags for Concrete or Mortar
Already know the volume? Enter it in m³ or cft, choose concrete grade or mortar ratio, and see the cement bags, cement weight and sand you need.
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Cement (50 kg bags)
9bags
- Cement weight
- 403 kg
- Sand
- 0.42 m³ · 14.8 cft
- Aggregate
- 0.84 m³ · 29.7 cft
Estimate only, based on standard thumb rules. Confirm quantities with your engineer or contractor before you buy.
Concrete: dry volume = wet × 1.54. Bags are rounded up.
Show working
- V dry = 1 m³ × 1.54 = 1.54 m³
- 1 : 1.5 : 3 → Σ = 5.5
- Cement = 1.54 ÷ 5.5 × 1440 = 403.2 kg ÷ 50 = 8.06 → 9
How to use
- Choose concrete or mortar.
- Enter the wet volume in m³ or cubic feet.
- Pick the grade or mix ratio to see bags, kg and sand.
Good to know
For concrete the wet volume is multiplied by 1.54 to get dry volume; for mortar by 1.33. Cement volume is the dry volume × cement share of the mix (for 1:6 mortar that is 1/7), converted at 1440 kg/m³ and divided by 50 kg per bag.
Thumb figures that follow from this: 1 m³ of M20 concrete needs about 8 bags, M15 about 6.4 bags, M10 about 4.4 bags; 1 m³ of 1:4 mortar about 7.7 bags and 1:6 mortar about 5.5 bags.
Use the Concrete, Brick or Plaster calculators if you only know the dimensions. Cement in India is sold in 50 kg bags (OPC 43/53 or PPC); the grade of cement does not change these volume-based quantities, but your engineer may adjust the mix.
Questions
How many bags of cement in 1 cubic metre of concrete?
For M20 about 8 bags, M15 about 6.4, M10 about 4.4 and M25 (1:1:2) about 11. Bags are rounded up.
How many bags for 100 cft of 1:4 mortar?
100 cft = 2.83 m³ wet. × 1.33 = 3.77 m³ dry; cement 1/5 of it = 0.75 m³ × 1440 = 1085 kg, so about 22 bags.
What is the volume of one cement bag?
50 kg ÷ 1440 kg/m³ = 0.0347 m³, about 1.23 cft.
Why is mortar factor 1.33 and concrete 1.54?
Mortar has no coarse aggregate, so it has fewer voids; 1.27–1.33 is used for mortar and 1.52–1.57 for concrete in Indian estimates.
Does cement grade (OPC 43 vs 53) matter here?
Not for this volume-based estimate. Grade affects strength and setting; your engineer may reduce cement with a design mix.