Estimate mortar volume, cement bags, sand, mixing water, masonry units, waste, and optional material cost for brick walls, concrete blocks, plaster or render, and projects with a known mortar volume.
Select the application, unit system, and mortar mix.
Enter the project measurements and mortar mix, then select “Calculate Materials.”
The calculator estimates wet mortar volume for masonry joints, plaster or render coats, or a custom volume. It then converts that amount into cement bags, sand, water, and optional cement cost.
For brickwork and blockwork, the calculator uses the unit face size plus the selected joint thickness to estimate the number of masonry units. It then subtracts the total solid unit volume from the wall volume.
Choose the measurement system that matches your project dimensions and preferred cement bag size.
Select brickwork, blockwork, plaster or render, or enter a known wet mortar volume.
For masonry, provide wall and unit dimensions. For plaster, enter the surface area, thickness, and number of coats.
Use the specified cement-to-sand ratio and add a realistic allowance for spillage, joint variation, and handling.
Use the cement bags, sand, water, volume, and unit estimates as a purchasing and planning guide.
| Cement : sand | Relative richness | General context | Important note |
|---|---|---|---|
| 1 : 3 | Rich | Selected high-strength or dense mortar applications | May be too strong or rigid for some masonry units |
| 1 : 4 | Medium-rich | General masonry or plaster applications where specified | Confirm compatibility with the substrate and unit type |
| 1 : 5 | General | Common planning ratio for general brickwork or plaster estimates | Use only when permitted by the project specification |
| 1 : 6 | Lean | Lower-strength general applications where approved | Not suitable for every exposure or structural condition |
| Designed mortar | Performance-based | Structural, heritage, exposed, or code-controlled masonry | Follow the approved mortar class and manufacturer data |
Net wall area equals wall length × wall height − doors and windows.
Approximate units equal net wall area ÷ modular face area × wall leaves. Modular face area includes the selected joint thickness.
Mortar volume equals gross masonry wall volume − total solid masonry unit volume. For plaster, wet volume equals area × thickness × number of coats.
Dry volume equals wet mortar volume × (1 + waste percentage) × dry-volume factor. This dry volume is divided according to the selected cement-to-sand ratio.
The amount depends on wall area, brick dimensions, joint thickness, wall leaves, openings, bond pattern, and waste. This calculator uses those inputs to estimate the mortar volume.
There is no single best ratio for every project. The correct mix depends on masonry strength, exposure, movement, structural requirements, local codes, and the approved specification.
Loose cement and sand occupy more space before mixing because of air voids and bulking. The dry-volume factor helps estimate the separate ingredients needed for a finished wet mortar volume.
Yes. Select plaster or render, enter the surface area, coat thickness, and number of coats, then set the required cement-to-sand ratio.
Large openings should generally be deducted. Small openings may be partly offset by cuts, returns, reveals, breakage, and mortar handling losses.
No. Sand moisture, absorption, weather, workability, additives, and the mortar specification all affect actual water demand. Add water gradually and follow the approved mix requirements.