Bagged mortar requirement and yield
Bag count is based on the units-per-bag yield you provide. Excess capacity is only a comparison with the stated coverage, not a prediction of leftover wet mortar. Actual joints and waste can change consumption.
For a brick wall unit takeoff before estimating mortar bags, the Brick Calculator provides the masonry count.
The formula
Use the coverage stated for the exact bag size and masonry unit. The estimate treats the supplier yield as a planning rate, adds the entered mortar allowance, and rounds the order upward to complete bags.
Worked example
With 200 standard blocks, a yield of 13 blocks per bag, and a 10% allowance, the order is ceiling(200 ÷ 13 × 1.10) = 17 bags. Their stated capacity is 221 blocks, leaving a nominal 21-block capacity beyond the entered count.
How to use this calculator
- Enter masonry units to lay, units laid per bag using the units shown.
- Set additional mortar allowance.
- Calculate and review mortar bags to purchase alongside the supporting quantities.
Use the right product coverage
A mortar label may give different yields for standard bricks and concrete blocks, and different bag masses have different coverage. Match all three before entering the rate. The default 13 blocks per bag corresponds to the cited 80 lb QUIKRETE Mortar Mix example; it is not a universal rate for every product or wall.
Job conditions affect consumption
Joint thickness, unit shape, surface condition, bedding style, handling loss, and interruptions can all affect yield. Review the manufacturer instructions and masonry specification. Mortar type is selected for the assembly separately. Grout poured into cores, concrete footings, and render coatings require separate quantity estimates and should not be treated as mortar bags in this model.
Assumptions & limitations
What this calculation assumes
- One unit type and one stated bag yield apply to the entire order.
What to keep in mind
- Does not derive mortar volume from joint geometry or choose mortar type.
Common questions
Can I estimate brick mortar?
Yes. Enter the bag’s stated brick yield rather than using the default block coverage.
Is bag weight enough to calculate coverage?
No. Product formulation and installation determine usable yield. Use the manufacturer coverage for the exact bag and unit type.
Does the allowance change the product yield?
No. It increases the quantity ordered above the coverage calculation. Actual yield remains dependent on the product and installation.
Sources & further reading
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