Sand and Cement Calculator
Precision estimation for UK mortar, screed, and rendering projects.
Material Estimates
For best results, use sharp sand for screeding and building sand for rendering/bricklaying.
Mortar & Screed Guide: Mix Ratios & Material Coverage
The Science of Mixing
The strength of your mortar or screed depends entirely on the ratio of sand to cement. Too much cement can cause cracking (shrinkage), while too little cement results in a weak, crumbly finish.
In the UK, we typically measure these mixes by volume (e.g., using a bucket). This calculator helps convert those volumes into weights so you can order the correct number of 25kg bags or bulk tonnes of sand.
UK Material Standards
- Sharp Sand:Coarse grit, used for floor screeds and paving bases.
- Building Sand:Fine/Soft sand, used for bricklaying mortar and rendering.
Standard Mix Ratios for UK DIY
1:3 Ratio (Extra Strong)
Best for heavy-duty rendering, water-resistant layers, or areas prone to high stress.
1:4 Ratio (Industry Standard)
The "go-to" mix for most floor screeds and standard rendering jobs across the UK.
1:5 Ratio (General Purpose)
Used for internal plastering or pointing work where flexibility is more important than pure strength.
1:6 Ratio (Mortar)
The standard mix for laying bricks or blocks in non-structural or internal applications.
The "Dry Volume" Rule
Did you know? When you mix sand, cement, and water, the total volume shrinks by about 20-30% as the air pockets are filled. This calculator accounts for that "bulkage" to ensure you don't run out of materials mid-job.
Sand & Cement FAQ
Technical Disclaimer
Estimates are based on standard dry densities. Actual coverage may vary based on moisture content in the sand, the exact brand of cement, and the substrate condition. For large structural projects, always consult with a professional UK contractor.