HesapHanem

Sand and Cement Mix Calculator

Enter the total volume and your sand ratio.

How it is calculated

You enter the finished (wet) volume of mortar in cubic metres and the number of sand parts for each 1 part of cement (4 means a 1:4 mix). The tool first adds 30% for the dry materials, because loose dry sand and cement shrink when mixed with water: dry volume = total × 1.3. That dry volume is split by the ratio: cement = dry ÷ (1 + parts) and sand = dry × parts ÷ (1 + parts). The number of bags is cement volume ÷ 0.0347 m³, rounded up to whole bags. Both inputs must be greater than zero. Water, lime, plasticiser and the moisture content of the sand are not considered, and the bag size of 0.0347 m³ is built in, so check it against the bags you actually buy.

Worked example

You need 0.5 m³ of mortar at a 1:4 mix. Dry volume: 0.5 × 1.3 = 0.65 m³. There are 1 + 4 = 5 parts in all. Cement is one part: 0.65 ÷ 5 = 0.130 m³. Sand is four parts: 0.65 × 4 ÷ 5 = 0.520 m³. Bags: 0.130 ÷ 0.0347 = 3.75, rounded up. The tool shows 4 bags of cement, 0.130 m³ of cement and 0.520 m³ of sand.

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Common mistakes

  • Entering the ratio as 1:4 or as 5 (the total parts). The field is the number of sand parts per one part of cement, so a 1:4 mix is entered as 4.
  • Entering the dry quantity you want to pour instead of the finished volume. The tool adds the dry allowance itself; typing a dry volume counts it twice.
  • Using litres or cubic feet. The volume is in cubic metres, so 500 litres must be typed as 0.5.
  • Treating the sand figure as bags or tonnes. It is a volume in m³; to order by weight you have to convert it using the density of your sand.
  • Buying exactly the bags shown for waste-prone jobs. The count already rounds up, but spillage, uneven surfaces and a different bag size can still leave you short.

About this calculator

Mixing mortar requires accounting for the fact that dry, loose sand and cement particles settle and compact once wetted, so the wet, in-place mortar volume is smaller than the sum of the dry ingredients poured in — this calculator applies a standard 1.3 dry volume factor to your target wet mortar volume, then splits that dry volume according to your chosen cement:sand ratio (such as 1:4 or 1:6) to find the cement volume, converts it to the number of 50 kg bags (roughly 0.0347 m³ per bag), and gives the corresponding sand volume.

Masons, DIY builders mixing mortar for brickwork or rendering, and site estimators use this to avoid the two common failure modes of eyeballing a mix: running short mid-batch, which risks an inconsistent mix if more dry material is added later, or over-ordering cement, which is one of the most expensive components by volume. Getting the ratio right also directly affects the cured mortar's strength and workability.

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  • Editorial team

    The sand volume shown assumes dry, loose sand. Damp sand bulks up, so a bucket of wet sand holds less actual sand than a bucket of dry sand, and a ratio measured by buckets on a rainy day can end up cement-rich. Treat the sand figure as a minimum if your pile is wet. Tell us what you are mixing for, such as bricklaying, rendering or screed, and which ratio you use.

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