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Cement Quantity Calculator

Get total cement, bag count and the cement/fly-ash split for a given volume and grade.

Quick answer

With the default inputs: Concrete volume 10 m³ · Concrete grade C30 · Fly ash replacement 0% etc.Total cement 3708 kg

Edit the inputs below to recalculate.
Cement1Sand1.84Gravel3Water0.53Per 1 m³ of concrete (schematic)
Figures below each bar are parts per unit of cement (C30 example); the cement content itself comes from the grade.

Inputs

m³
%
Typically 15-25%; up to 30% for mass concrete
%

Result

Total cement
3708kg
Volume with waste10.30m³
Cement per m³360kg
Total cement3.71t
50 kg bags75bags
Total fly ash0kg
Total binder3600kg
Binder per m³360kg/m³

Reference values for the same grade. Actual contents vary with aggregate grading, admixtures and supplementary materials; the approved mix design governs.

Formula

Volume with wasteV_total = V × (1 + waste %)
Cement per m³mc = reference × (1 − replacement %)
Total cementM = mc × V_total
BagsN = ceil(M ÷ 50)
Fly ashmf = reference × replacement % × 1.15
10 m³ of C30 with 3% waste: 360 kg/m³, so 3600 kg total — 3.60 t or 72 bags of 50 kg. At 20% fly ash, cement drops to 288 kg/m³ (about 2966 kg total) plus roughly 828 kg of fly ash.

How to work it out

  1. Fix the use and grade first — masonry M5/M7.5/M10, plaster M10/M15, concrete C20-C40 all take very different cement quantities.
  2. Take cement mass per cubic metre (or per square metre) from the mix, in kilograms.
  3. Multiply by total volume or area.
  4. Convert to bags at 50 kg, or tonnes for bulk delivery.
  5. Add 2-3% for torn bags, damp and lumps; allow 1% for tank residue on bulk.

Where it goes wrong

Material and cost

Bagged P.O 42.5 runs about 400-480 per tonne and bulk 350-430, so bulk is 8-12% cheaper but needs a silo. A 10,000 m² residential frame uses roughly 800-1,200 tonnes, so a 50 per tonne difference is 40,000-60,000. Cement also has a shelf life: strength starts to fall after three months and requires retesting after six.

On site

Basis

FAQ

How much is a bag of cement?
The standard bag in China is 50 kg, marked 50±1 kg. Some small plants sell 40 kg or 45 kg bags that look cheaper per bag but cost more per tonne. Always convert using the actual pack weight rather than counting bags.
Why is fly ash used in excess of the replacement level?
Fly ash contributes little early strength, so equal-mass replacement loses strength. Practice is to replace 20% of cement but add 1.15-1.3 times that mass. The benefits are lower heat of hydration, better workability and lower cost; the price is slower early strength and poorer carbonation resistance, so use it cautiously in winter and in precast work.
Can I cost a job from the cement quantity alone?
It gives material cost only, not total cost. Concrete also carries aggregate, admixture, batching, haulage, pumping, testing and waste. For site-mixed concrete use these figures; when buying ready-mix, price by volume and use the cement figure only to sanity-check the supplier's mix.

Cite this page

Use this format in reports, method statements or coursework. The link is permanent.

Building Calculator. Cement Quantity Calculator. 2026-10-25. https://jianzhujisuan.com/en/cement-quantity

Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.