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Cement Mortar Calculator

  • 1:3 (strong, external render)
  • 1:4 (standard, bricklaying)
  • 1:5 (light mortar)
  • 1:6 (internal plaster)
Results
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Plan your masonry and plastering projects with confidence. Our Cement Mortar Calculator estimates how many bags of cement and yards of sand you'll need for bricklaying, wall rendering, and floor screeds.

Standard mix ratios vary by application: 1:4 for brickwork, 1:6 for internal plaster, and 1:3 for external rendering. Our calculator defaults to the most common 1:4 ratio but lets you adjust as needed. Always add 5-10% extra for waste — small projects often run short due to mixing losses and uneven application.

Formula
Cement bags = Volume × MixRatio_Cement / (CementDensity × BagSize)

FAQ

What is a standard mortar mix ratio?
For bricklaying (M10): 1 part cement : 4 parts sand by volume. For internal plastering (M5): 1:6. For external rendering (M15): 1:3.
How much does an 80lb bag of cement cover?
A typical 80lb bag covers about 0.6 cu ft of mortar at a 1:4 mix ratio, or roughly 100 sq ft of ½-inch plaster.

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