Concrete material calculator
Work out the cement bags, sand and aggregate for any pour — from length × breadth × depth or a direct volume — using IS nominal mixes from M5 to M25.
It applies the standard 1.54 dry-volume factor, reports quantities in both m³ and cft, and can take your local cement and aggregate rates to estimate material cost. A planning-level tool, computed in your browser.
Pour details
Plan length of the member or slab.
Plan width of the member or slab.
e.g. a 150 mm slab = 0.15 m.
IS nominal mixes (cement : sand : coarse aggregate). Lower grades suit blinding & mass work; M20/M25 suit RCC.
Enter local prices to estimate material cost.
Price of one 50 kg bag.
Fine aggregate, per cubic foot.
Coarse aggregate, per cubic foot.
Cement required
15 bags
14.5 bags exact · 50 kg each · 1:1.5:3 mix
Dry volume
2.77 m³
Wet volume
1.80 m³
Sand
26.7 cft
Aggregate
53.4 cft
Sand + agg
2.27 m³
| Material | Volume (m³) | Quantity |
|---|---|---|
| Cement | 0.50 | 15 bags |
| Sand (fine) | 0.76 | 26.7 cft |
| Aggregate (coarse) | 1.51 | 53.4 cft |
| Dry volume | 1.80 m³ × 1.54 = 2.77 m³ |
| Cement (1 bag) | 50 kg ≈ 0.0347 m³ (density 1440 kg/m³) |
| cft conversion | 1 m³ = 35.3147 cft |
A planning-level estimate using IS nominal mix ratios and a 1.54 dry-volume factor. Actual quantities vary with aggregate grading, moisture, bulking of sand, water–cement ratio and wastage (add ≈5–10%). For structural RCC, follow a designed mix and your engineer's bar bending & concrete schedule.
From wet volume to bags on site
Concrete quantities start from the finished volume you need, scaled up to account for the voids in the dry materials, then split by the mix ratio.
Dry volume
Take the wet (finished) volume and multiply by 1.54 — dry sand, aggregate and cement bulk down once mixed and compacted.
Split by ratio
Divide the dry volume in the mix proportions (e.g. M20 = 1:1.5:3) to get the cement, sand and aggregate volumes.
Bags & cft
Convert cement volume to 50 kg bags (÷ 0.0347 m³) and sand/aggregate to cubic feet (× 35.3147) for ordering.
Concrete quantities, answered
How do I calculate the concrete for a slab?+
First find the wet volume — for a slab that is length × breadth × thickness in metres (e.g. a 4 × 3 m slab that is 150 mm thick = 4 × 3 × 0.15 = 1.8 m³). Multiply by 1.54 to get the dry volume, then split it by the mix ratio to get cement, sand and aggregate. This calculator does all of that for you.
Why multiply the wet volume by 1.54?+
Dry sand, aggregate and cement have voids between the particles. When water is added and the mix is compacted, the dry materials bulk down by roughly 54%. So the volume of dry ingredients needed is about 1.54 times the finished (wet) concrete volume. The 1.52–1.57 range is common; 1.54 is the usual textbook value.
How many cement bags are in 1 m³ of cement?+
A 50 kg bag of cement has a volume of about 0.0347 m³ (cement density ≈ 1440 kg/m³), so 1 m³ of cement is roughly 28.8 bags. The calculator divides the cement volume from your mix by 0.0347 and rounds bags up, since you cannot buy a part bag.
What do the mix ratios like 1:2:4 mean?+
They are the proportions, by volume, of cement : sand : coarse aggregate. M15 (1:2:4) means one part cement to two parts sand to four parts aggregate. Higher grades have more cement: M20 is 1:1.5:3 and M25 is 1:1:2. These are IS nominal mixes suitable for ordinary work; structural concrete should use a designed mix.
Which concrete grade should I use in Nepal?+
M5–M10 suit blinding, levelling and mass (non-structural) work. M15 is common for plain concrete and light footings. M20 and M25 are the usual choices for reinforced concrete — slabs, beams, columns and footings — in ordinary residential building. Always follow the structural drawings and your engineer's specification.
Does this include wastage and steel?+
No. The result is the theoretical material quantity. Add about 5–10% for wastage, spillage and over-excavation, and order steel reinforcement separately from the bar bending schedule. Water is also not counted; it is added on site to the specified water–cement ratio.
Sources & data note
Based on IS 456 / IS 10262 nominal mix proportions, a 1.54 dry-volume factor, a 50 kg cement bag of ≈0.0347 m³ (density 1440 kg/m³) and 1 m³ = 35.3147 cft. Quantities are indicative — actual needs vary with aggregate grading, sand bulking, water–cement ratio and wastage (add ≈5–10%). Material rates change frequently; verify current local prices before ordering, and follow your engineer's designed mix for structural RCC.