Engineering & Construction Calculators: Brass, Bricks, RMC & Steel

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The brass unit: why half of India buys sand by volume

In Maharashtra and neighbouring states, sand, aggregate and earth are sold by the brass: 100 cubic feet, or 2.832 m³. A brass of damp river sand weighs around 4.5 tonnes; a brass of 20 mm gitti about 4.4 tonnes. Elsewhere the same material is often quoted per tonne, which is why comparing two quotes can feel like comparing apples and oranges. The brass calculator converts between them in one step.

Bricks, cement and sand for a wall

A traditional Indian brick is 9 × 4½ × 3 inches (230 × 110 × 75 mm); the modular brick in IS 1077 is 190 × 90 × 90 mm. With a 10 mm mortar joint you need roughly 408 traditional or 500 modular bricks per cubic metre of brickwork. Brickwork in 1:6 cement mortar uses about 1.25 bags of cement per cubic metre, which is roughly one bag for every 3.5 m² of a 9-inch wall. The brick calculator works this out for your wall length, height, thickness and mix.

Ready-mix concrete (RMC): order the right number of loads

RMC is sold by the cubic metre and delivered in transit mixers of about 6–7 m³. Volume is simply length × width × thickness, but always add 3–5% for spillage, uneven formwork and pump line losses. IS 456 sets the grades: M20 is the common minimum for reinforced slabs and footings in houses, and M25 is common for columns and multi-storey work. The RMC calculator turns slab and footing sizes into cubic metres and mixer trips.

Steel pipe and tube weight

Steel is sold by weight, so knowing kg per metre lets you check a fabrication bill line by line. Every steel calculator here uses a density of 7,850 kg/m³:

Pipe (kg/m)       = (OD − t) × t × 0.02466        (OD and t in mm)
Square tube (kg/m) = (4 × A − 4 × t) × t × 0.00785  (approx., A = side in mm)
Weight            = kg/m × length (m) × number of pieces

Pipe sizes follow IS 1239 (light, medium, heavy classes) and IS 1161 for structural tubes; square and rectangular hollow sections follow IS 4923. The MS pipe, square tube and rectangular tube calculators include common Indian sizes so you don't have to measure wall thickness yourself.

Site habits that save money

• Measure deliveries, not heaps. A dumped heap spreads out and looks smaller; the truck body is the honest measure.
• Account for bulking. Damp sand swells 20–30%, so a brass of wet sand holds less sand.
• Add wastage once, at the end. About 5% for bricks, 3–5% for concrete and 2–3% for steel offcuts; don't add it at every step.
• Keep IS sizes on the order. Writing the IS grade and class on a purchase order stops under-weight pipe and thin tube.