Work out the wet volume of a slab, beam, column or footing from its dimensions, then split that volume into cement bags, sand and coarse aggregate for any nominal mix from M5 to M25 — the same quick checks an estimator runs before framing the abstract of cost.
Pick the member type, enter the three dimensions in metres, and get the wet (compacted) volume of concrete. Enter a slab thickness of 125 mm as 0.125 m.
Slab: length and breadth of the panel in plan, D = slab thickness.
Every rectangular member — slab panel, beam, column shaft or pad footing — is simply length × breadth × depth. This is the same figure you would book in the details of measurement, so the calculator also shows it in cft for cross-checking older records kept in imperial units.
Enter the wet volume of concrete and pick the nominal mix. The calculator applies the 1.54 dry-volume factor, splits the dry volume by mix proportions, and converts cement volume into 50 kg bags — exact and rounded up for ordering.
Dry ingredients occupy more volume than the compacted concrete they produce, because mixing water and compaction close the voids. The trade convention is a dry-volume factor of 1.54 for concrete. The dry volume is then divided in the ratio of the mix proportions, and the cement share is converted to bags at 1440 kg/m³ (one 50 kg bag = 0.0347 m³, so 28.8 bags fill one cubic metre).
Handy while pricing an analysis of rates or checking a contractor's material indent against booked quantities.
| Grade | Mix (c : s : a) | Cement (m³) | Cement (bags) | Sand (m³) | Aggregate (m³) | Typical use in works |
|---|---|---|---|---|---|---|
| M5 | 1 : 5 : 10 | 0.096 | 2.77 | 0.48 | 0.96 | Levelling course, mud-mat below footings |
| M7.5 | 1 : 4 : 8 | 0.118 | 3.41 | 0.47 | 0.95 | Lean concrete, mass fill |
| M10 | 1 : 3 : 6 | 0.154 | 4.44 | 0.46 | 0.92 | PCC in foundation trenches, flooring base |
| M15 | 1 : 2 : 4 | 0.220 | 6.34 | 0.44 | 0.88 | Plain concrete works, DPC beds |
| M20 | 1 : 1.5 : 3 | 0.280 | 8.06 | 0.42 | 0.84 | General RCC — slabs, beams, columns of small works |
| M25 | 1 : 1 : 2 | 0.385 | 11.09 | 0.39 | 0.77 | RCC in more heavily loaded members |
Concrete quantities rarely travel alone — steel and consumption norms usually follow.
Brickwork, earthwork, flooring & paint, steel and unit converters — the full set for the estimating table.
Browse calculators →Bar weight by d²/162, bar-bending totals and standard dia weights per metre for reinforcement estimates.
Open steel calculator →Cement, sand, aggregate and steel consumption per unit of finished item — for indents and theoretical-consumption checks.
View consumption norms →