Mortar Calculator
Turn a brick or block count into a mortar order using the coverage for your joint, unit, and bag. Product coverage is the controlling input.
What does the mortar calculator calculate?
Divide the number of masonry units by the manufacturer’s expected units per bag, add waste, and round up. Coverage changes with unit size, wall thickness, joint width, tooling, spillage, and bag weight. Use a product data sheet or supplier estimate matched to the actual assembly.
Mortar bags from product coverage
Manufacturer or supplier coverage converts the project’s unit count into bags for a stated unit and joint configuration. Waste is then added and the answer rounded to whole packages.
How to measure for an accurate estimate
- Complete the brick or block count before estimating mortar.
- Identify unit dimensions, wall thickness, joint width, and joint depth for a matching coverage rate.
- Read units-per-bag from current product data or ask the masonry supplier.
- Separate wall sections that use different units, joints, or mortar products.
Mortar for 500 units
A wall uses 500 masonry units; one bag covers 40 units and the plan allows 10% waste.
500 ÷ 40 × 1.10 = 13.75, so purchase 14 bags; at 80 lb each, dry weight is 1,120 lb.Before you purchase material
- Use the mortar type specified by the designer; stronger is not automatically more suitable.
- Buy compatible products from a consistent lot when color matters on exposed joints.
- Store bags dry and elevated, and reject hardened or moisture-damaged material.
- Plan small enough batches to place within the manufacturer’s usable time and weather limits.
Common questions
How many blocks will one bag of mortar lay?
There is no single reliable count. Coverage depends on block dimensions, wall thickness, joint width and depth, frog or core geometry, workmanship, and bag size. Use the product data for your assembly or request a supplier estimate.
What type of mortar should I use?
Mortar type depends on masonry, exposure, structural demands, compatibility, and project specifications. Do not select it solely from a quantity calculator. Follow approved plans, applicable code, and guidance from the designer, manufacturer, or building authority.
How much mortar waste should I include?
Ten percent is a common budgeting allowance, but experienced crews on simple work may use less and complex or highly tooled work may use more. Product coverage may already assume typical loss, so check how the stated rate was developed.
Can I estimate mortar from wall square footage instead?
Yes, when the product provides square-foot coverage for the same unit and joint configuration. Unit-count coverage is often easier after completing a block or brick estimate. Never mix a square-foot rate with a unit count without converting.
Sources and reference standards
- Brick Industry Association — Technical NotesIndustry technical guidance for brick dimensions, mortar joints, estimating, and construction.