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Mortar Quantity Calculator

Work out mortar quantity instantly with clear inputs, formula shown and shareable results.

About Mortar Quantity Calculator

Mortar occupies the joints, typically 15-25 percent of the masonry volume depending on unit size and joint thickness. Wet mortar volume is multiplied by 1.33 to allow for the bulking and void filling of dry sand, and the dry volume is split by the mix parts, with cement converted to bags at 1440 kg/m³.

Formulas

Mortar volume

Wet m³ = wall area x thickness x mortar share

Materials

Dry = wet x 1.33; cement m³ = dry / (1 + sand parts); bags = cement m³ x 1440 / 50

Worked example

With the default values below, Mortar Quantity Calculator returns Cement required of 12.6. Change any input above and every figure here is recalculated in your browser.

Inputs used

Wall areaminimum 0.1 m²
50 m²
Wall thicknessminimum 50 mm
230 mm
Mortar mixone of 1 : 4 cement to sand, 1 : 5 cement to sand, 1 : 6 cement to sand
1 : 6 cement to sand
Mortar share of masonry volumeaccepts 5–40 %
20 %

Results

Cement required
12.6 bags
Wet mortar volume
2.300 m³
Sand required
2.622 m³
Dry material volume
3.059 m³

Step by step

  1. 1Values used
  2. 2Mortar volume
  3. 3Materials
  4. 4Cement required= 12.6 bags
  5. 5Wet mortar volume= 2.300 m³
  6. 6Sand required= 2.622 m³
  7. 7Dry material volume= 3.059 m³

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Mortar Quantity figure worked out?

Wet m³ = wall area x thickness x mortar share. Mortar occupies the joints, typically 15-25 percent of the masonry volume depending on unit size and joint thickness.

Which mix should I use?

1:6 suits general internal brickwork, 1:5 external walls and 1:4 load-bearing or exposed work. A stronger mortar than the units themselves causes cracking through the bricks rather than the joints.

What values do I need to enter?

This calculator takes 4 inputs: Wall area, Wall thickness, Mortar mix, Mortar share of masonry volume. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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