Cement Bag Weight: 50 kg in m³ and cft
One standard cement bag in India weighs 50 kg net. That is about 1.226 cft or 0.0347 m³ of loose cement, at 1,440 kg/m³ bulk density.
So 28.8 bags make 1 m³ of loose cement, and 20 bags make one tonne. Concrete needs fewer bags per m³ because sand, aggregate and water fill most of it.
For quantities in actual work, use the cement calculator for concrete, brickwork and plaster. For purchase costs, see cement prices per 50 kg bag.
Convert bags, kg, m³ and cft
Enter any one unit to see all four, using 50 kg bags and loose bulk density of 1,440 kg/m³.
- 50 kg bags
- 1
- kg
- 50
- m³ of loose cement
- 0.034722
- cft of loose cement
- 1.226205
Bags may be fractional for conversion. Volume is loose cement, not concrete output or the outside dimensions of a sack.
One bag of cement in m³, litres and cft
One 50 kg bag is 0.0347 m³, 34.7 litres or 1.226 cft of loose cement.
50 ÷ 1,440 = 5/144 = 0.034722222… m³
0.034722222… × 1,000 = 34.722222… litres
(50 ÷ 1,440) × 35.3147 = 1.226204861… cft ≈ 1.226 cft
Bags per m³ of loose cement = 1,440 ÷ 50 = 28.8
Uses 35.3147 cft per m³, rounded from the exact foot-to-metre conversion; NIST's SI conversion table gives 1 international foot = 0.3048 m exactly.
| 50 kg bags | Net kg | m³ | cft |
|---|---|---|---|
| 1 | 50 | 0.03472 | 1.226 |
| 5 | 250 | 0.17361 | 6.131 |
| 10 | 500 | 0.34722 | 12.262 |
| 20 | 1,000 | 0.69444 | 24.524 |
| 28.8 | 1,440 | 1.00000 | 35.315 |
| 100 | 5,000 | 3.47222 | 122.620 |
Where the 1,440 kg/m³ density is used
1,440 kg/m³ is the loose bulk density of cement commonly used in Indian quantity estimates; it is not the density of solid cement particles.
Our cement, concrete, plaster and sand calculators all use it. CPWD Specifications 2009, Volume 1, cement-mortar proportioning take a 50 kg bag as 0.035 cum for volume measurement, a rounded batching figure close to 50 ÷ 1,440.
Do not use loose bulk density in an absolute-volume mix design; that needs the cement's specific gravity and the approved mix data. Loose volume also changes as cement settles or is aerated.
Example: 10 bags × 50 = 500 kg; 500 ÷ 1,440 ≈ 0.3472 m³, or 12.262 cft of loose cement before mixing.
OPC, PPC and PSC bag weights
OPC, PPC and PSC all come in the same 50 kg bag.
OPC is ordinary Portland cement, PPC is Portland pozzolana cement and PSC is Portland slag cement. BIS product manuals cover 50 kg packing for OPC under IS 269 and PPC under IS 1489 (Part 1), and allow smaller packs too. Which pack sizes you can buy depends on the brand and dealer.
For a smaller pack, use the converter's kg input: 25 kg is half of a 50 kg bag and 1 kg is 0.02 bag. The converter's “bags” unit always means 50 kg.
Net weight excludes the sack. Check the declared quantity and BIS licence details on the pack. The BIS OPC product manual, section 3 specifies marking and refers to Legal Metrology requirements.
Cement per m³ of nominal concrete
The nominal M20 estimating mix needs 8.064 bags, or 403.2 kg, per m³ of finished concrete before wastage.
These rows use the same mix engine as our cement calculator: dry volume = wet concrete volume × 1.54, and cement share = cement parts ÷ total parts. They are estimating figures, not a mix design.
| Nominal estimating mix | Cement kg | 50 kg bags |
|---|---|---|
| M7.5 (1:4:8) | 170.58 | 3.412 |
| M10 (1:3:6) | 221.76 | 4.435 |
| M15 (1:2:4) | 316.80 | 6.336 |
| M20 (1:1.5:3) | 403.20 | 8.064 |
M20 arithmetic: 1 × 1.54 ÷ (1 + 1.5 + 3) = 0.28 m³ of loose cement; 0.28 × 1,440 = 403.2 kg; 403.2 ÷ 50 = 8.064 bags. Round up the final project purchase quantity after applying your allowance, rather than rounding each m³ separately.
IS 456:2000, clause 9.3 permits nominal mixes for M20 or lower where applicable; its Table 9 is mass-based, not this shorthand volume-ratio table. Use an approved design mix for M25 and above. For mortar and plaster, use the cement calculator.
Frequently asked questions
What is the weight of one cement bag in India?
50 kg net. That is the standard bag for OPC, PPC and PSC. Smaller packs are also sold, so check the net quantity printed on the bag.
How many cft are in one bag of cement?
About 1.226 cft of loose cement, taking bulk density as 1,440 kg/m³: 50 ÷ 1,440 × 35.3147 = 1.2262 cft. This is an estimating volume, not the size of the sack or the concrete it makes.
How many cement bags make one cubic metre?
28.8 bags of loose cement: 1,440 ÷ 50 = 28.8. One cubic metre of concrete needs far fewer because sand, aggregate and water fill most of it; nominal M20 (1:1.5:3) takes 8.064 bags by this method, before wastage.
How many 50 kg cement bags make one tonne?
20 bags: 1,000 kg ÷ 50 kg = 20. Ten bags weigh 500 kg and 100 bags weigh 5,000 kg, or 5 tonnes, on the labelled net-weight basis.
Do OPC, PPC and PSC bags weigh different amounts?
No. A 50 kg bag holds 50 kg net whichever type it is. Their bulk densities can differ, so the loose volume per bag may not be identical; use the product’s measured density when volume matters.
Why do some references use 0.035 m³ or 1.25 cft per bag?
CPWD Specifications 2009 take a 50 kg bag as 0.035 m³ for volume batching. 50 ÷ 1,440 gives 0.034722 m³, about 0.8% less. 0.035 m³ is about 1.236 cft; 1.25 cft is a coarser site rounding.
Next step: enter your concrete, wall or plaster sizes in the cement calculator for bags and sand.