Estimate mortar for brickwork and concrete block masonry before buying material. Enter wall dimensions, masonry-unit dimensions and mortar-joint thickness, or start from a known unit count or known mortar volume. The calculator estimates litres and cubic metres, then converts the result into whole bags using the exact yield you enter from the product data sheet.
Choose the method that matches the information you already have. Wall modes estimate mortar from wall and unit geometry; the other modes let you begin with a known masonry-unit count or known mortar volume.
Your result will appear after you press Calculate Mortar.
Bag estimate appears only when you enter a positive product yield per bag.
Bed joints and vertical perpend joints occupy part of a masonry wall's volume. The calculator estimates that space from the wall, unit size and average joint thickness.
Keep wall geometry, joint volume, waste, product yield and cost separate so each assumption is easy to check.
See estimated mortar volume in litres for easy comparison with product yield.
View the same quantity in cubic metres for larger masonry jobs.
Brick and block modes show an approximate masonry-unit count.
Add your own contingency for real site and workmanship variation.
Enter the exact litres-per-bag yield and round up to whole bags.
Enter a current A$/bag price for a simple material-only budget.
A mortar estimate starts with the space between masonry units. A wall is not made entirely from brick or block and it is not made entirely from mortar. The useful quantity is the difference between the gross masonry-wall volume and the volume occupied by the masonry units. This Mortar Calculator models that difference from the dimensions you enter.
For a regular wall, the calculator creates a modular face size for each brick or block. The module is the unit length plus one average vertical joint and the unit height plus one average bed joint. Net wall area is divided by the module area to estimate the number of units. Theoretical unit volume is then subtracted from gross wall volume to estimate mortar.
Mortar ≈ Wall Volume − Theoretical Masonry Unit VolumeThis is a planning estimate rather than a detailed masonry take-off. Real units can have frogs, cores, perforations, webs, face shells and bedding patterns that change consumption. Bond patterns, wall ends, corners, piers, returns, cut units and joint finishing also influence the amount of mortar used.
Multiply wall length by wall height, then subtract major openings such as windows and doors. A wall 8 m long and 2.4 m high has 19.2 m² of gross area. If openings total 3 m², the net masonry face area is 16.2 m². The calculator includes an opening field so you do not need to pretend the openings are filled with masonry.
Openings still create cuts, jambs, ends and detailing, so an area subtraction is not a perfect final take-off. For a highly detailed wall, break the elevation into simpler sections and estimate each one separately.
Masonry products vary. Enter the length, height and depth of the actual unit from the manufacturer or project documents rather than relying on a generic standard size. The unit depth is important because it controls the depth of the mortar joints and therefore the joint volume.
If a cavity wall uses different masonry products on each leaf, calculate the leaves separately. The wall-leaf field is best used only when the same unit and joint geometry is repeated.
The NCC Housing Provisions masonry section provides a nominal 10 mm reference for conventional bed and perpend joints unless otherwise specified. That does not mean every masonry system uses a 10 mm joint. Thin-bed products, special units and project-specific details can use different dimensions. Enter the joint required by the actual project.
Small changes in average joint thickness can add up across hundreds or thousands of units. Leaving the input blank until you provide a value makes that assumption visible instead of hiding it inside the calculator.
Brick Wall mode is designed for a regular wall or wall section. Enter length, height, brick dimensions, joint thickness, openings and the number of identical leaves. The calculator estimates the number of brick modules and the joint volume represented by the wall.
Brick frogs and perforations can affect real consumption. A simple rectangular model treats the unit by its external dimensions, so the result should be compared with manufacturer coverage information when available.
Concrete block masonry uses the same face-module idea, but hollow units require extra caution. Many concrete blocks are not laid on a completely solid bed across the full footprint. Face-shell bedding, webs, reinforced cores and grout can make the actual mortar volume different from a solid-geometry model.
Do not combine grout or core fill with mortar. They are separate materials. Use the Concrete Block Estimator for block quantity and a concrete or grout calculator for filled cores where required.
If you already know the number of bricks or blocks, select Known Unit Count. The calculator estimates an average modular joint volume per unit from unit dimensions and joint thickness. This is useful for a quick purchasing check but can slightly overstate joints around the external perimeter because not every unit has a complete joint on all sides.
If drawings, estimating software or a supplier schedule already gives a mortar volume, enter that quantity directly. The calculator accepts litres, cubic metres or cubic feet and then applies waste, bag yield and price. This mode is also useful for repointing when you have calculated the actual repair-joint volume separately.
Mortar bag yield varies by product, formulation, bag weight and application. A premixed general masonry mortar, a mason mix, a thin-bed product and a repair mortar should not be assumed to produce the same number of litres from the same bag weight. The calculator therefore requires the exact approximate yield from the product data sheet.
If you leave Mortar Yield Per Bag blank, the calculator still shows litres and cubic metres but does not invent a bag count. This makes the volume result useful even when the product has not yet been selected.
Whole Bags = Mortar With Waste (L) ÷ Yield Per Bag (L) → Round UpIf a wall requires 180 L of mortar after waste and the chosen product yields approximately 15 L per bag, 180 ÷ 15 = 12 bags. If the result is 12.1, buy 13 complete bags before adding any separate spare-bag decision.
Mortar waste depends on workmanship and geometry. Material can be squeezed from joints, dropped from the trowel, left in the mixer or discarded after its usable working time. Irregular masonry, deep joints, many cuts and inexperienced laying can increase consumption. A repetitive wall built efficiently can be more predictable.
There is no single percentage that is correct for every job, so waste starts at a true empty field. Enter a percentage only after considering the actual conditions.
The calculator answers “how much mortar?” It does not choose the correct mortar. NCC masonry provisions reference AS 3700 and AS 4773 and include acceptable mortar mixes for certain housing applications. The correct mix depends on masonry material, exposure, structural requirements and project documentation.
Do not change cement, lime, sand or proprietary product proportions simply because a cheaper mix looks attractive. Bond, durability, compatibility, workability and structural requirements can all be affected.
The NCC masonry provisions also contain joint-detail guidance. Conventional bed and perpend joints are nominally 10 mm unless otherwise specified, and there are restrictions on raked joints in saline environments and areas with heavy industrial airborne pollution. Those rules show why a quantity calculator is not a substitute for masonry detailing.
Some clay bricks contain frogs or perforations. Depending on laying method, mortar can enter those spaces and increase consumption compared with a simple rectangular-unit model. If the manufacturer publishes mortar consumption or coverage data for the specific brick, compare that information with the calculator result.
Hollow blocks can use face-shell bedding rather than a solid mortar bed. Reinforced masonry may also include grout in selected cores. The calculator estimates conventional joint space from external unit geometry, so it should be treated as a planning model rather than a detailed face-shell quantity survey.
Repointing is different from laying a new wall because only part of the existing joint depth is removed and replaced. For repointing, estimate total joint length × joint width × rake-out depth, then use Known Mortar Volume to convert that result into bags and cost. Do not use the full wall depth for a shallow repointing repair.
Some AAC, large-format masonry and proprietary systems use thin-bed mortar or adhesive layers much thinner than conventional masonry joints. Entering a thin joint can model the geometry, but the manufacturer's stated coverage is normally the better purchasing reference for proprietary products.
Enter the current local price per bag and the calculator multiplies that price by the final whole-bag quantity, including any spare bags you deliberately add. It does not include brick or block cost, wall ties, lintels, reinforcement, scaffolding, mixer hire, labour, sand delivery, disposal or other project costs.
If the masonry is supported on a concrete footing, calculate that separately with the Concrete Footing Calculator. For concrete columns or piers, use the Concrete Column Calculator.
| Project | Main Inputs | Useful Result | Important Check |
|---|---|---|---|
| Single-Leaf Brick Wall | Wall + brick + joint | Litres + brick count | Actual brick dimensions |
| Concrete Block Wall | Wall + block + joint | Litres + block count | Bedding method |
| Known Unit Schedule | Count + unit + joint | Approx. mortar | Bond and perimeter |
| Known Mortar Quantity | Litres / m³ / ft³ | Bags + cost | Product yield |
| Repointing | Calculated repair volume | Bags + cost | Actual rake depth |
Every numeric field starts empty. The soft zero is only a placeholder, not a real value. If you type 10, the field contains 10 rather than 010. If you type 230, it contains 230 rather than 0230. Typed numbers remain sharp and fully readable.
Reset clears all numeric fields again instead of inserting real zeros. This preserves the clean look while removing the unwanted leading-zero behaviour.
Mortar, bricks, concrete and masonry materials can contain crystalline silica. Safe Work Australia explains that respirable silica can be generated when brick, concrete or stone is cut, drilled, ground, chiselled or otherwise mechanically processed. Follow current regulator guidance, product safety data sheets and the controls required for the task.
Mortar is used to bed and bond masonry units and to form the visible joints between them. Grout is usually a more fluid material used to fill masonry cores or cavities around reinforcement. Render is a surface coating, while concrete is a separate structural material made with coarse aggregate. These materials may all appear on the same masonry project, but their quantities should not be combined.
A reinforced block wall, for example, can need block-laying mortar in the bed and perpend joints plus grout in selected or fully filled cores. The mortar calculator estimates only the joint material. If cores are filled, calculate that volume separately using the hollow-core geometry or the project schedule.
Bagged premixed mortar can simplify small jobs because the dry ingredients are proportioned by the manufacturer. Site-mixed mortar may be more practical for larger masonry work where cement, lime, sand and approved additives are batched on site to the required specification. The correct approach depends on project scale, specification, storage, labour and quality-control requirements.
This calculator works with either method because the first result is volume. If you use bagged mortar, enter the product yield to convert litres into bags. If mortar is site mixed, use the litre or cubic-metre result as a planning quantity and follow the specified mix proportions and batching procedure rather than trying to convert the whole job into generic bags.
Published yield is normally an approximate value achieved under stated mixing conditions. Actual yield can be influenced by water content, measuring accuracy, material compaction, sand moisture, mixing method and how much material remains in the mixer or wheelbarrow. Product instructions should be followed because adding excess water simply to increase apparent volume can reduce performance.
The calculator treats product yield as an input rather than a promise. If a bag is stated to produce a certain number of litres, use that figure as the planning conversion and still allow for real site losses where appropriate.
A flush, ironed, weather-struck or raked joint does not leave exactly the same finished mortar geometry. Joint tooling can compact mortar and remove some surface material. Raking deliberately removes mortar from the face to a controlled depth. These differences are usually smaller than the effect of wall size and joint thickness, but across a large wall they can affect consumption.
Where the joint profile is specified, use a waste allowance that reflects the finishing method and do not assume removed mortar will be cleanly reusable. The NCC also places limitations on raked joints in certain exposure conditions, so joint profile is a detailing decision as well as a quantity issue.
Running bond, stack bond, English bond, Flemish bond and other masonry patterns distribute vertical joints differently. Some patterns also change the number of headers, cuts and returns. The modular calculation on this page assumes a regular repeating face module, which is suitable for planning but does not model every bond detail individually.
If the wall contains decorative bond work, many small piers or frequent returns, divide the project into sections and compare the result with a manual course-by-course take-off. A detailed brick schedule can be especially useful when special shapes or different unit sizes are mixed in the same elevation.
Masonry piers can use considerably more mortar per square metre of visible elevation than a flat wall because there are more corners, returns and internal joint faces. A simple wall-area estimate may therefore understate the work. If a pier has a regular plan shape, estimate its masonry courses and units separately rather than adding only its front face area to the wall.
Concrete structural columns are different from masonry piers. If the project includes poured columns, estimate those separately with the Concrete Column Calculator.
Openings do not simply remove wall area. Around windows and doors there may be lintels, sills, flashing, weep details, cut units and additional jointing. Subtracting the opening area is still a useful first step, but the exact mortar quantity around the perimeter can differ from a plain wall.
For a high-accuracy estimate, calculate the main uninterrupted wall first and then add separate allowances for complex opening details rather than trying to force everything into one average percentage.
Hot, windy, cold or wet conditions can affect masonry work, water demand, workability and curing. Those conditions do not change the geometric joint volume, but they can affect how efficiently mortar is mixed and used. Material that dries too quickly, becomes contaminated or exceeds its allowable working time may be discarded, increasing actual consumption.
Plan the quantity together with the laying rate. Buying or mixing far more mortar than the crew can place within the product's usable time can create waste even if the original volume calculation is accurate.
Dry bagged mortar should be stored according to manufacturer instructions and protected from moisture. A damaged or partially hydrated bag may not perform as intended. If the project needs a large number of bags, think about dry storage space and delivery sequencing before adding a large spare-bag allowance.
Extra unopened bags can be useful insurance on a small project, but too many leftovers tie up money and may be difficult to store for future use. The separate Extra Spare Bags field lets you make that purchasing decision independently of geometric waste.
Start with the masonry schedule or product dimensions rather than estimating unit size by eye. Measure the net wall area, identify every masonry type and separate different wall thicknesses. Enter the joint thickness from the project documents. For unusual walls, create several smaller calculations and add the mortar volumes together.
After the geometry is complete, compare the result with a manufacturer's coverage table or an experienced supplier's estimate. If the two figures are close, confidence improves. If they differ significantly, check whether the difference comes from hollow units, face-shell bedding, unit perforations, waste, bond pattern or a different definition of coverage.
Before ordering, confirm the final wall dimensions, masonry unit, mortar specification and product availability. Recalculate if the wall design changes or if openings are added. For bagged products, use the exact current yield and bag price from the supplier. For site-mixed mortar, confirm the specified batching method and material proportions.
Keep a small written record of the assumptions used: wall area, unit size, joint thickness, waste percentage and product yield. The PDF button is included for this reason. It provides a simple project summary that can be compared with supplier quotes or revised measurements.
Mortar type, exposure suitability, proportions and masonry compatibility belong to the project specification—not the bag-count formula.
Use the specified bed and perpend joint size.
Brick, block, stone and proprietary units can need different mortar.
Durability conditions can affect mortar and joint requirements.
Follow drawings, NCC provisions, standards and product instructions.
Answers to common questions about brick mortar, block mortar, joints, bags and waste.
Estimate gross wall volume, calculate the theoretical brick volume from unit and joint dimensions, then subtract the brick volume. This calculator performs those steps from the measurements you enter.
Yes. Choose Block Wall. Hollow blocks and face-shell bedding can make real consumption differ from the simple geometry estimate, so compare with manufacturer information.
Use the value specified for the project. NCC Housing Provisions include a nominal 10 mm reference for conventional bed and perpend joints unless otherwise specified.
Enter the litres yielded by one bag of the exact product. The calculator divides mortar with waste by that yield and rounds up to whole bags.
Mortar products vary in formulation, bag weight and finished yield. A universal default can create a misleading result.
No. Mortar joints and grout-filled block cores are separate material volumes.
Yes through Known Mortar Volume after you calculate the joint repair volume from joint length, width and rake-out depth.
You can enter a thin joint geometrically, but proprietary systems should generally be purchased from manufacturer coverage data.
No. Mortar specification is a design and compliance decision based on the project, masonry, exposure and applicable requirements.
The blurred zero is only a placeholder. It is not a real field value, so typing 10 produces 10 rather than 010.
Silica-containing masonry materials can generate respirable crystalline silica when mechanically cut, drilled, ground or processed. Follow current safety guidance.
Use current building requirements, product data and workplace safety guidance alongside any online mortar estimate.
Masonry-unit, mortar-mix and mortar-joint provisions with references to AS 3700 and AS 4773.
View Masonry ProvisionsAustralia's primary technical design and construction provisions for buildings.
Visit NCC OnlineNational guidance on respirable crystalline silica risks in construction and masonry work.
Read Silica GuidanceUse the exact product's yield, water requirements, limitations and safety information when converting litres into bags.