Concrete and brick estimator
Cement, sand and aggregate for a concrete volume, and bricks and mortar for a wall. An ordering estimate, not a structural design.
Concrete
84.7 bags of cement16.17 m³ dry volume, from 10 m³ wet at M20 (1 : 1.5 : 3)
| Cement | 84.7 bags (4,236 kg) |
|---|---|
| Sand | 4.41 m³ |
| Aggregate | 8.82 m³ |
| Water (at 0.5 w/c) | 2,118 litres |
Brickwork
3,365 bricksincluding 5% wastage, half brick wall
| Bricks | 3,365 |
|---|---|
| Mortar volume | 1.04 m³ |
| Cement (1:4 mortar) | 8 bags |
| Sand | 1.11 m³ |
An ordering estimate, not a structural design. The mix for a real member comes from the drawing and the engineer responsible for it. Site materials vary in bulk density and moisture, so order against these figures and expect to adjust.
Why 1.54 m³ of dry material makes 1 m³ of concrete
Dry cement, sand and aggregate are full of voids. When you add water and mix, cement paste fills the gaps between sand grains and the resulting mortar fills the gaps between the aggregate, so the whole batch loses bulk. One cubic metre of finished wet concrete needs about 1.54 cubic metres of dry material.
Values between 1.52 and 1.57 are all in common use depending on how the aggregate is graded. This tool uses 1.54, the usual teaching figure, and shows the dry volume alongside the result so you can see where the number came from rather than taking it on trust.
Nominal mixes
- M5 (1 : 5 : 10)Levelling and blinding
- M7.5 (1 : 4 : 8)Mass concrete, blinding
- M10 (1 : 3 : 6)Non-structural fill
- M15 (1 : 2 : 4)Flooring, kerbs, light work
- M20 (1 : 1.5 : 3)Slabs, beams, columns in housing
- M25 (1 : 1 : 2)Heavier structural work
These are volumetric proportions of cement, sand and coarse aggregate. They are rules of thumb for ordering, not design mixes. Anything carrying load in a real building is specified by grade and verified by cube test, not by counting bags on site.
How the brick count works
Each brick occupies its own face area plus one mortar joint on each visible edge, so a 230 by 55 mm Nepali brick with a 10 mm joint takes up 240 by 65 mm of wall. Dividing the wall area by that gives the count for a half-brick wall; a full-brick wall doubles it. Mortar is then the wall volume minus the volume the bricks themselves occupy, which is more honest than the flat percentage some calculators use.
Civil engineering at ICE
Concrete Technology & Masonry is a core subject in Year 3 of theBE Civil Engineering program at ICE. This tool covers the same take-off arithmetic students apply during the Estimating & Costing unit and on real site assessments. The long-hand version, worked the way a site engineer does it, is in concrete and brick quantity take-off.
Common questions
- Is this Concrete and brick estimator page free to use?
- Yes. Every Kaamko tool is free, with no sign-up, no account and no usage limit. They are published by Imperial College of Engineering, a Tribhuvan University-affiliated engineering college in Tathali, Bhaktapur, and are not funded by advertising.
- Does what I type get sent anywhere?
- No. This tool runs entirely in your browser: the calculation happens on your own device, nothing you type is uploaded, and nothing is stored after you close the page.
- Where do the figures come from?
- Each tool names its source on the page, along with the date that source was read. Where a rate or a slab is provisional — announced in a budget speech but not yet gazetted, for instance — the page says so rather than presenting it as settled.
- Who maintains these tools?
- Imperial College of Engineering, formerly Janakpur Engineering College, in Tathali, Bhaktapur, Nepal. Corrections are welcome by phone on 01-5091616 or through the contact page, and a figure reported as wrong is checked against its published source rather than adjusted on request.
Last checked by Imperial College of Engineering. Rates, slabs and formulas are re-checked against their published source on this date.