Concrete calculator

The Pakistan Bureau of Statistics' survey for August 2026 found a truck of 100 cft of pit sand at Rs 7,406 on average across the 34 cities with a sand price, about Rs 74 a cft: Rs 7,998 in Lahore, Rs 8,233 in Karachi and Rs 13,631 in Islamabad. Prices ran from Rs 2,932 in Hyderabad to Rs 15,165 in Abbottabad. Sand is cheap where it is dug and dear where it is carted far, and coarse sand for concrete, such as Chenab or Lawrencepur sand, costs more than the pit sand the survey prices.

In August 2026 a truck of 100 cft of crush cost Rs 10,973 on average across the 35 cities the Pakistan Bureau of Statistics surveyed, about Rs 110 a cft: Rs 18,773 in Lahore, Rs 9,253 in Karachi and Rs 16,522 in Islamabad. Prices ran from Rs 4,466 in Khuzdar to Rs 18,996 in Sahiwal. Crush is quarried stone, so the haul from the quarry is much of its price, and it costs more on the plains of Punjab than in cities near the hills.

Multiply the length by the width by the depth, all in feet, and by the number of pieces; a depth in inches is divided by 12 first. A 40 x 30 ft slab 6 in thick is 600 cft, and ten footings of 4 x 4 ft, 18 in deep, are 240 cft. A round column 12 in across and 10 ft high is 7.85 cft. Divide cft by 35.31 for cubic metres.

For every 100 cft, 17.6 bags of cement, 44 cft of coarse sand and 88 cft of crush, before wastage. With 2% on the cement and 5% on the rest, buy 18 bags, 46.2 cft of sand and 92.4 cft of crush. A 600 cft slab takes 108 bags, 277.2 cft of sand and 554.4 cft of crush, about 2.8 and 5.5 trolleys.

In 1:2:4, 6.2 bags of cement (311 kg), 0.44 cubic metres of sand (15.5 cft) and 0.88 cubic metres of crush (31.1 cft). In 1:1.5:3, 7.9 bags (396 kg), with 0.42 cubic metres of sand and 0.84 cubic metres of crush. In 1:3:6, 4.4 bags. These are before wastage.

Because the dry materials pack into less room once water is added: the sand fills the gaps between the stones, and the cement the gaps in the sand. It takes about 1.54 cft of loose cement, sand and crush to make 1 cft of concrete, which also allows for sand that bulks when damp. Some estimates use 1.52 or 1.57, which changes the answer by a bag or two in a hundred.

The number is the strength a test cube reaches after 28 days: 15 and 20 newtons a square mm, about 2,200 and 2,900 psi. M15 is made as 1:2:4 and M20 as 1:1.5:3, which takes about 27% more cement. Most house slabs, beams and columns are 1:2:4, with 1:1.5:3 where the engineer asks for it, and lean 1:4:8 or 1:3:6 goes under footings and floors. Always follow the structural drawings.

About half the cement's weight, so 25 litres to a 50 kg bag: 440 litres for 100 cft of 1:2:4. More water makes concrete easier to place but weaker and more prone to cracks, so add only what the mix needs to be worked into place, and keep it wet afterwards while it cures.

No. It works out the concrete and what goes into it. Weigh the bars on the steel weight calculator, and for a roof slab the roof slab calculator adds the steel and the shuttering area too.