Masonry Mortar Calculator
Add each wall or area separately to get a full material breakdown
Metric (m)
Imperial (ft / in)
Walls / Areas
Typical 10%. Stone or complex work: 15-20%.
Job Costing
Enter costs in your local currency - the calculator works with any currency as long as values are consistent.
UK Market Prices
Fills in the material cost fields using current UK retail prices sourced from major trade suppliers. Prices are updated regularly by BuildersCalc and give you a realistic starting point for your estimate. Always cross-check against your own quotes before finalising.
Results
| Wall / Area | Area (m²) | Net Mortar (m³) | + Waste | Total (m³) |
|---|
Total Area
-
m² net (after deductions)
Net Mortar
-
m³ before waste
Total to Mix
-
m³ inc. waste
Mix Ratio
-
cement : sand
Material Quantities
| Material | Per m³ mortar | Net total | + Waste | Order qty |
|---|
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Frequently Asked Questions
How much mortar do I need per square metre of brickwork?
For standard UK brickwork with 10 mm joints in stretcher bond: approximately 0.025 m³ of mortar per m² of wall face. For blockwork (440 x 215 mm blocks): approximately 0.012 m³ per m² - about half that of brickwork. Always add 10-15% for waste.
What mortar mix should I use for brickwork?
Standard general brickwork: 1:5 or 1:6 cement to soft sand (designation iii). For exposed or structural work: 1:4 (designation ii). Adding lime (e.g. 1:1:5 cement:lime:sand) improves workability. Never use mortar stronger than the bricks themselves - it will crack the bricks rather than the joints during movement.
What is the correct mortar joint thickness for brickwork?
The standard joint thickness is 10 mm. Joints should be no less than 6 mm and no more than 16 mm. Perpend (vertical) joints must be fully filled. For tooled or recessed feature brickwork, 10-12 mm joints are used to allow enough depth for the weathering profile.
What waste allowance should I use for mortar?
Add 10-15% to your calculated mortar quantity for droppings, over-filling and adjustments. Use 15% for complex work with many returns, reveals and cut bricks. Site conditions and joint thickness variations both affect actual usage compared to calculated quantities.
What Building Regulations apply to mortar in brickwork?
Mortar must meet Part A (Structure), referencing BS EN 998-2 for masonry mortar. Below-ground mortar must be sulphate-resistant where soils or groundwater contain high sulphate levels (Parts A and C). For repointing, always use mortar no stronger than the original - stronger mortar traps moisture and damages the masonry.
How do I calculate how many bags of mortar I need?
Calculate total wall area (length x height), subtract openings, then multiply by 0.025 m³/m² for brickwork or 0.012 m³/m² for blockwork. Convert to bags using the coverage on the product packaging. Or use the calculator above - it does all of this automatically for standard UK brick and block sizes.