Estimate the number of 50kg cement bags needed for a wall, slab, column or beam. Enter the dimensions and pick a mix ratio.
Includes a standard 1.54× dry-volume factor for bulking and wastage. Need sand and aggregate too? Use the Concrete Mix Calculator for the full recipe.
The ratio (cement : sand : aggregate) controls strength. M15 (1:2:4) covers most residential slabs, beams and general RCC work. M20 (1:1.5:3) is stronger, used for columns and heavy-duty or commercial slabs. M10 (1:3:6) is a lean mix for leveling courses and non-structural fill, not for load-bearing work.
Wet (cast) concrete is denser than the loose dry materials that go into the mixer — sand and aggregate compact once mixed and vibrated. A 1.54× multiplier on the wet volume is the standard allowance used across Pakistani construction to size material orders correctly.
Order 5–10% more than the calculated figure. Spillage during transport and mixing, uneven site conditions, and bag breakage all eat into the raw number.