Cement & Concrete Calculator
सिमेन्ट तथा कंक्रिट क्याल्कुलेटर
Estimate cement bags, sand, aggregate, water and material cost for a concrete pour, with wastage and editable local prices.
Estimate cement bags, sand, aggregate and water for a slab, footing or column. Choose a nominal mix, allow for wastage, and edit the local prices to match your supplier.
- Mix
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- Wet volume
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- Dry volume
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- Cement mass
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- Cement bags
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- Sand
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- Coarse aggregate
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- Water (approx.)
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- Material cost
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- Cost per m³
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Cost breakdown
| Material | Quantity | Rate | Amount |
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About the cement and concrete calculator
This calculator turns a slab, footing or column volume into the cement, sand, aggregate and water you need to buy. Enter the length, width and thickness — mixing feet with inches is fine — choose a nominal mix such as M20 (1 : 1.5 : 3), set a wastage allowance, and the result gives cement bags, sand and aggregate in cubic feet, water in litres and an editable material cost. It uses the standard site method, so it is a purchase estimate rather than a structural design.
How the quantities are worked out
The wet volume is length × width × thickness in cubic metres. Dry materials bulk up when mixed, so the wet volume is multiplied by a dry-volume factor of 1.54. Each material then takes its share of the mix: for M20, cement is 1 part, sand 1.5 parts and aggregate 3 parts out of 5.5. Cement volume is converted to mass at 1,440 kg per cubic metre, then divided into 50 kg bags and rounded up, because you cannot buy part of a bag. Sand and aggregate are converted to cubic feet, the unit most Nepali suppliers quote.
Nominal mixes and when they stop being enough
M7.5 (1 : 4 : 8), M10 (1 : 3 : 6), M15 (1 : 2 : 4) and M20 (1 : 1.5 : 3) are nominal mixes — fixed volume ratios used on small and medium buildings. They are convenient but do not guarantee strength, because the actual cement content, water and aggregate grading vary. M25 and above should be a tested design mix, and anything structural should follow the drawings and the engineer's specification. The calculator flags this when you pick M25, but the same caution applies to any mix on a critical element.
Wastage, water and real sites
A 5% wastage allowance is a sensible default for bag work and site mixing; increase it for small pours, rough ground or a site where bags are opened and left standing. Water is shown at a water–cement ratio of 0.5, which is workable for many mixes but too wet for some exposures and too dry for others. More water makes concrete easier to place and weaker when it sets, so treat the litres as a starting point and follow the mix design or the engineer's instruction.
Local prices
Material prices move with location, transport and the season. The defaults — Rs 730 per 50 kg bag of cement, Rs 115 per cft of sand and Rs 120 per cft of aggregate — are indicative Kathmandu Valley rates for October 2026, and every one of them is editable. Enter the rates your supplier has quoted. The cost shown is materials only: it excludes labour, steel reinforcement, formwork, pumping, transport and VAT, all of which can be a large part of the final bill.
Units and accuracy
Length and width can be in feet or metres; thickness can be in inches, millimetres, centimetres, metres or feet. That covers the common Nepali site mix of a room measured in feet and a slab measured in inches. The result is rounded for display, but the underlying calculation keeps full precision, so a small change in thickness does not produce a misleading jump. For a large or structural pour, order against the engineer's bar-bending schedule and mix design, not this estimate alone.