Cement Calculator
IS-code based estimation for concrete, plastering and brickwork — get accurate bag counts, sand and aggregate before you order.
How this is calculated
The 1.54 factor exists because dry, loose cement + sand + aggregate occupy more volume than the same materials once mixed with water and compacted — the voids between aggregate particles get filled. IS 456:2000 and standard estimation practice use 1.54–1.57; this tool uses 1.54.
Wet volume = L × B × D
Dry volume = Wet volume × 1.54
Cement vol = Dry volume × (1 ÷ sum of ratio)
Cement bags = Cement vol ÷ 0.0347 m³/bag
Sand / Aggregate = Dry volume × (their ratio ÷ sum) → converted to cft
One bag of cement (50 kg) occupies 0.0347 m³, based on a loose bulk density of ~1440 kg/m³. 1 m³ = 35.3147 cft.
Why does my dealer's bag count never match a simple calculator?
Most basic calculators skip the dry volume factor entirely, or use a flat "add 10%" rule. Concrete needs ×1.54, plaster needs ×1.33 — using the wrong one under- or over-orders by a noticeable margin on a full house. This tool applies the correct factor per work type.
Should I order the exact quantity this shows?
Order the wastage-adjusted figure, not the theoretical one. Spillage, bag breakage, and short mixing batches are normal on any site — 5% extra cement and 5-8% extra sand is standard allowance we build into every estimate for clients.
Does the cement grade (OPC 43 vs 53) change this calculation?
No — bag count is a volume/weight calculation independent of grade. OPC 53 gains strength faster and suits RCC work; OPC 43 is fine for plaster and brickwork. Choose grade for strength and curing time, not quantity.
What if my site measurements are in running feet, not sq ft?
For plaster and brickwork, multiply running length × height yourself before entering — this tool expects the finished area or wall face, not linear footage. For irregular walls, break the wall into rectangles and add the areas.