Site & estimation
Construction Material Calculator — Cement, Sand, Aggregate, Bricks & Steel
Quick quantity take-offs for site work: cement, sand and aggregate for a concrete mix, bricks and mortar for brickwork, plaster and paint for wall areas, and reinforcement steel weight using the D²/162 rule (kg per metre for a bar of diameter D mm).
Concrete
Nominal mix by volume. For design mixes (M25 and above in RCC), use the mix design's cement content.
Allowance
Handling and site wastage — 2% to 5% is typical.
Cement
0 bags
How this is worked out
Concrete: dry volume = wet volume × 1.54, split by the mix ratio. Cement at 1,440 kg/m³, 50 kg a bag.
Brickwork: bricks = volume ÷ (brick size + joint on each face). The rest of the volume is mortar; dry mortar = wet × 1.33.
Plaster: wet volume = area × thickness; dry = wet × 1.27. Steel: kg per metre = D² ÷ 162.
These are estimating figures — go by the approved mix design and bar bending schedule for actual orders.
Frequently asked questions
How do I calculate the weight of a steel bar?
Weight in kg per metre = D² ÷ 162, where D is the bar diameter in mm. For example, a 12 mm bar weighs 144 ÷ 162 ≈ 0.89 kg per metre.
How many cement bags are needed for 1 m³ of M20 concrete?
For a nominal 1 : 1.5 : 3 mix, about 8 bags of 50 kg per cubic metre, using a dry-volume factor of about 1.54. Design mixes vary, so use your mix design where you have one.
Figures are for planning. The conditions in your tender document or contract always take precedence.
Let the calculators fill themselves in
With a free Digi Karya account, these tools pull in your own contracts, tenders, bills and documents — and you also get licence and GST expiry reminders, a tender workspace, milestone billing and EMD & bank guarantee tracking.