Construction Material Estimator
Estimate cement, sand, aggregate, bricks and steel for concrete, walls and plaster.
"How many cement bags do I need?" has a real answer, and it depends on the mix ratio, the dry-volume factor and how much wastage you allow. This estimator handles concrete, brickwork and plastering, converts everything through standard construction practice, and prices it with your local material rates.
What are you building?
Result
Fill in the fields above and your result will appear here.
What the Construction Material Estimator does
Material estimation works backwards from volume. For concrete, wet volume is multiplied by 1.54 to get dry volume — the ingredients occupy more space loose than they do compacted — and then split according to the mix ratio. For masonry and plaster the factor is 1.33.
Brick quantities come from the volume of one brick including its mortar joint, which is why a 190 × 90 × 90 mm modular brick with a 10 mm joint behaves as 200 × 100 × 100 mm. Steel is estimated as a percentage of concrete volume, which varies by element — a column carries far more reinforcement than a footing.
How to use this tool
- Choose the type of work: concrete, brickwork or plastering.
- Enter the dimensions. Thickness is in inches for concrete and millimetres for plaster, matching site practice.
- For walls, deduct a percentage for doors and windows — 10–15% is typical for a residential wall.
- Select the mix or mortar ratio your engineer has specified. M20 at 1:1.5:3 is the usual residential structural mix.
- Enter your local material rates to get a cost. Rates vary substantially between districts.
Formula and method
CONCRETE
Wet volume = Length × Width × Thickness
Dry volume = Wet volume × 1.54
Cement = Dry × (cement part ÷ total parts), converted at 1,440 kg/m³
Cement bags = Cement kg ÷ 50
Sand, aggregate = Dry × (their parts ÷ total parts)
Steel = Wet volume × element percentage × 7,850 kg/m³
BRICKWORK
Wall volume = Area × Thickness
Bricks = Wall volume ÷ (brick volume including mortar joint)
Mortar = Wall volume − (bricks × brick volume), then × 1.33 for dry volume
PLASTER
Volume = Area × Thickness, then × 1.33 for dry volume
Worked example
Example: a 20 × 15 ft slab, 5 inches thick, M20
| Wet volume | 125 cu ft (3.54 m³) |
| Dry volume (×1.54) | 5.45 m³ |
| Cement (1 part of 5.5) | ≈ 29 bags |
| Sand (1.5 parts) | ≈ 52 cu ft |
| Aggregate (3 parts) | ≈ 105 cu ft |
| Steel at 1% for a slab | ≈ 292 kg |
Including 5% wastage. At typical rates that is roughly ₹47,000 of material for the slab alone, before labour and shuttering.
What your result means
Cement bags are rounded up, since you cannot buy a fraction of a bag. Order slightly more rather than less — a mid-pour shortage is expensive.
Sand and aggregate in cubic feet matches how suppliers in India actually sell, usually by the tractor or tipper load. Confirm what volume a load contains locally.
The steel figure is indicative only. Actual reinforcement comes from the structural drawings and the bar bending schedule. Use this for budgeting, never for ordering.
Important considerations
- These are nominal mix estimates. For structural work, a design mix from a testing laboratory is what should be used, and M25 and above are almost always design mixes.
- Sand quality matters. Silty or very fine sand increases both cement consumption and the risk of cracking.
- Wastage of 3–5% is normal for careful work; 8–10% is realistic where storage and handling are poor.
- Shuttering, curing water, labour, admixtures and equipment are not included — material is typically 55–65% of the cost of a structural element.
- Brick sizes vary regionally. Measure a sample from your actual supplier rather than assuming a standard size.
- Deduct properly for openings. On a wall with large windows, a 12% deduction may be far too low.
Limitations of this tool
- It estimates a single element at a time. A full house requires each slab, beam, column, wall and plastered surface to be calculated and added.
- Steel is a percentage-based approximation and cannot replace a bar bending schedule.
- It does not account for site conditions, weather, workmanship or compaction quality, all of which affect real consumption.
- Foundation work, waterproofing, flooring, plumbing and electrical materials are outside its scope.
Frequently asked questions
How many cement bags for 1 cubic metre of M20 concrete?
About 8 bags. The dry volume is 1.54 m³, of which one part in 5.5 is cement — roughly 0.28 m³, which at 1,440 kg/m³ is around 403 kg, or 8 bags of 50 kg.
How many bricks in 100 square feet of 9-inch wall?
Roughly 1,000–1,100 traditional bricks including mortar joints, depending on the exact brick size and joint thickness. The calculator computes it from the brick dimensions you select.
Why multiply wet volume by 1.54?
Because cement, sand and aggregate occupy more space loose than they do once mixed and compacted. The 1.54 factor accounts for the voids that disappear during mixing and compaction; for mortar the equivalent factor is 1.33.
Is this enough to order material for my house?
For budgeting and for cross-checking a contractor's estimate, yes. For actual ordering, work from your structural drawings and have a quantity surveyor or your engineer prepare a proper bill of quantities.