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Estimate cement for concrete, masonry, plastering and floor screed — metric or imperial units, mix presets, wastage, bags and optional bag price.
Last updated: Aug 2026
cement_kg = wet_m³ × dry_factor × (c / Σparts) × 1440 × (1 + wastage%)
Concrete uses dry factor 1.54; plaster, masonry mortar and screed use 1.33. Unit conversion uses the shared construction calculation engine helpers.
Estimate cement for concrete, masonry mortar, plastering and floor screed — or reverse: how much work can N bags cover? See kilograms, bags, wastage, formula steps and limitations. Indicative planning figures only.
Example (concrete): 1 m³ of M20 (1:1.5:3) with 5% wastage. Dry volume = 1 × 1.54 = 1.54 m³. Cement fraction = 1/5.5. Cement ≈ 1.54 × (1/5.5) × 1440 ≈ 403 kg before wastage, ≈ 423 kg after 5% wastage → about 9 bags of 50 kg.
After computing kilograms, divide by your bag size (commonly 25, 40 or 50 kg) and round up to whole bags for purchasing.
For concrete: cement_kg = wet_volume_m³ × 1.54 × (cement_parts / total_parts) × 1440 × (1 + wastage%). For plaster, masonry mortar and screed the dry factor is typically 1.33 and aggregate parts are usually zero.
Bags = ceil(cement_kg ÷ bag_size_kg). Varnarc supports common 25 kg, 40 kg and 50 kg bag sizes. Always confirm the bag weight printed by your supplier.
Presets such as M15 (1:2:4) and M20 (1:1.5:3) are common planning ratios. Use the mix specified by your structural engineer for actual construction — this tool is indicative only.
Site spillage, uneven thickness and handling losses mean purchased cement often exceeds the theoretical quantity. A 5–10% allowance is common for planning.
Where the mix includes sand, Varnarc shows the related dry sand share so you can plan mortar/concrete materials together. Verify moisture and bulking on site.