Rules of thumb for estimating materials

Design IRL Editorial · Figures checked 7 November 2026 · For owners checking a contractor's bill of quantities (BOQ) · How we make our guides

You don't need to calculate every bag of cement. A few rules of thumb are enough to spot a BOQ that is far too high or suspiciously low.

Cement, steel, sand and bricks calculator →House construction cost calculator →Flooring and tiles calculator →Paint calculator →

How to use these numbers

These rules apply to a low-rise RCC frame house and are per sq ft of built-up area (BUA). They are approximate. Sources disagree, soil and design change the steel, and your engineer's drawings always win.

Use them to ask questions. If a quote is 30% off these figures, ask the contractor to explain why.

The structure: cement, steel, sand, aggregate, bricks

Material	Per sq ft of BUA	Notes
Cement	0.4 bags	0.35–0.40 single storey; 0.40–0.50 for G+1 or G+2
Steel	4 kg	Range 3.5–4.5 kg; some G+1 houses reach 5–5.5 kg
Sand	1.2–1.8 cft	Sources disagree widely
Coarse aggregate	1.35 cft	Range 1.0–1.5 cft
Bricks	5–5.5 bricks	9 inch outer walls, 4.5 inch partitions

Finishes: tiles, paint and putty

Tiles: about 1.3 sq ft of tile per sq ft of BUA, covering floors and dado.
Paint: about 0.18 litres per sq ft of BUA overall, around 0.14 inside and 0.4 outside.
Interior emulsion covers about 120–170 sq ft per litre per coat. Economy paints cover less.
Water-based primer covers about 180–220 sq ft per litre per coat.
Putty quantities vary a lot by product. Read the pack or datasheet.

Check the tin

Coverage depends on the wall and the product. The manufacturer's datasheet is always more reliable than a thumb rule.

Allow for wastage

Material	Wastage allowance
Cement	2–3%
Steel	3–5%
Tiles	5–10% (more for diagonal layouts)
Sand and aggregate	8–12%
Paint	2–5%

Small items such as binding wire, admixtures and consumables add another 8–12% of material cost. A BOQ with no allowance for these is incomplete.

Where the money goes

Materials are commonly 50–65% of the build cost and labour 30–45%. Within material cost, a widely used Indian split looks like this.

Item	Share of material cost
Steel	About 18–25%
Cement	About 16%
Sand	About 12%
Coarse aggregate	About 7–8%
Finishers: bricks, tiles, paint	About 16–17%
Fittings: doors, windows, electrical, plumbing, sanitary	About 23%

This is a share of material cost, not of the total cost.

Checking a contractor's BOQ

Ask every bidder to quote against the same BOQ, so the lines can be compared one by one. A contractor who won't share a BOQ is a warning sign.
Multiply your built-up area by the rules above and compare totals for cement, steel and bricks.
Check that the BOQ names the grade or brand of each material, not just the quantity.
Look for a wastage allowance and a line for small items. Missing lines often reappear later as extras.
Check whether the rates include GST, cartage and unloading. Handling and lifting can add 1–2%.

Steel is where estimates differ most, because it depends on the structural design. If the steel figure looks high or low, ask your structural engineer to confirm it from the drawings.

Worked example: a 2,000 sq ft house

Material	Rough quantity
Cement	800–1,000 bags
Steel	8–9 tonnes
Sand	2,500–3,600 cft
Coarse aggregate	About 2,700 cft
Bricks	10,000–11,000
Tiles	About 2,600 sq ft, plus 10%
Paint	About 360 litres

Approximate, before wastage except where noted.

Prices for these materials change month to month and city to city. Get 2–3 quotes for steel and cement, and keep a 10–15% contingency in your overall budget.

Find the people

Sources

Most published cost figures come from firms that sell the work. We give ranges and you should get 2–3 quotes.