About this calculator
Estimates mortar quantities for brick or block masonry from a volume-per-area or volume-per-unit consumption rate, split by an editable cement:lime:sand proportion into cement bags, sand, and water.
Formula
base volume = area (m²) × volume per m² (L) [per-area mode]
or unit count × volume per unit (L) [per-unit mode]
total volume (incl. waste) = base volume × (1 + waste% / 100)
cement volume = total volume × cement parts / (cement + lime + sand parts)
lime volume = total volume × lime parts / (cement + lime + sand parts)
sand volume = total volume − cement volume − lime volume
cement mass = cement volume × cement bulk density
cement bags = ceil(cement mass / bag mass)
sand mass = sand volume × sand bulk density
water volume = total volume × water ratio
The cement:lime:sand proportion is a plain editable ratio (e.g. 1:1:6), not a strength class — EN 998-2 classifies mortar by compressive strength (M2.5, M5, M10...), which depends on the actual materials and testing, not just the mix ratio you enter here.
Worked example
Defaults: 10 m × 2.5 m area, 25 L/m² consumption, 1:1:6 proportion, 10% waste.
base volume = 25 m² × 25 L/m² = 625 L
total volume incl. waste = 625 × 1.10 = 687.5 L
cement = lime = 687.5 × 1/8 = 85.9375 L each; sand = 515.625 L
cement mass = 85.9375 L × 1400 kg/m³ = 120.3 kg → ceil(120.3/25) = 5 bags
sand mass = 515.625 L × 1500 kg/m³ = 773.4 kg
water = 687.5 × 0.18 = 123.75 L
FAQ
Why doesn't the calculator ask for a strength class (M5, M10...)? Strength class depends on the actual materials and site conditions, not just a volume ratio — this calculator only converts a proportion you choose into quantities, it doesn't verify or guarantee a resulting strength class.
Where do "volume per m²" and "volume per unit" come from? They depend heavily on joint thickness and unit size, so they're not something this calculator derives — enter a rate from your mortar manufacturer's data sheet or your own site measurement.
Why doesn't the calculator cite a standard?
EN 998-2 covers mortar strength classification, not a quantity take-off formula or a fixed
proportion, so meta.standards is left empty.
Assumptions and limits
Volume-per-area/per-unit consumption, bulk densities, cement bag size, and the water ratio are all disclosed estimates you should adjust to match your own product and site conditions.