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Cement Mortar Calculator

For 1 m³ of 1:6 cement mortar: dry volume = 1 × 1.33 = 1.33 m³, cement = 1.33 ÷ 7 = 0.19 m³ = 5.47 bags of 50 kg, and sand = 1.33 × 6 ÷ 7 = 1.14 m³. A richer 1:4 mix needs 7.66 bags per m³.

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Behind this panel: an example with the default sizes.

Inputs

Results update as you type.

Mortar
m³
Factors
Mortar 1:6Mortar 1:61Cement: 5.47 bags6Sand: 1.14 m³myconstructioncalculator.com
Diagram updates as you type.

Results

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Cement (50 kg bags)
5.47bags
Sand1.14 m³
Cement weight274 kg
Water (approx.)137 L
Bags to buy6 bags
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Working
  1. Dry volume = 1.000 × 1.33 = 1.330 m³
  2. Cement = 1.330 ÷ (1 + 6) = 0.190 m³ → ÷ 0.0347 m³ per bag = 5.47 bags
  3. Sand = 1.330 × 6 ÷ 7 = 1.140 m³
  4. Water = cement weight × 0.50
Results are estimates for planning and material ordering only. They are not a substitute for structural design or approval by a qualified engineer. Read the full disclaimer.
Formula


Dry volume   = wet volume × 1.33
Cement       = dry ÷ (1 + n)           → ÷ 0.0347 m³ per 50 kg bag
Sand         = dry × n ÷ (1 + n)
Water        = cement weight × water–cement ratio


Worked Example


1 m³ of 1:6 cement mortar:


    

  1. Dry = 1 × 1.33 = 1.33 m³
    2. 

  2. Cement = 1.33 ÷ 7 = 0.19 m³ = 5.47 bags (274 kg)
    3. 

  3. Sand = 1.33 × 6 ÷ 7 = 1.14 m³
    4. 

  4. Water ≈ 274 × 0.5 = 137 L
    5. 



Cement and Sand per m³ of Mortar






Mix
Cement (50 kg bags)
Sand (m³)






1 : 3
9.58
1.00




1 : 4
7.66
1.06




1 : 5
6.38
1.11




1 : 6
5.47
1.14




1 : 8
4.26
1.18






Worked Examples
Frequently Asked Questions
How many bags of cement are in 1 m³ of 1:6 mortar?
About 5.5 bags (50 kg), by the dry volume method. 1:4 needs about 7.7 bags and 1:3 about 9.6 bags.
Why multiply mortar volume by 1.33?
Dry cement and sand take up more space than the mortar they make, because water and cement fill the gaps between sand grains. About 33% extra dry material is needed.
Which mortar ratio should I use?
Commonly 1:4 for load-bearing and exposed brickwork, 1:5–1:6 for general walls, and 1:8 for non-structural partitions. Follow your specification.
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