Mortar Calculator
Enter brick (or block) count or wall area. We'll tell you how many bags of mortar mix to buy.
Advanced options
- Units
- 0
- Joint volume
- 0 cu ft
- Coverage per bag
- 0 units
- Estimated cost
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How the mortar calculator works
Mortar fills the joints between bricks/blocks. The volume needed = the surface joint area × joint depth, plus an allowance for the head joints. The empirical rule used by mason supply houses:
- ~125 modular bricks per 60-lb bag at ⅜" joints (single-wythe veneer).
- ~25 standard 8"×16" CMU blocks per 60-lb bag at ⅜" joints.
- Wider joints or rougher units = fewer bricks/blocks per bag.
Mortar types — pick by use
- Type N — 750 psi. Above-grade exterior veneer, chimneys, soft brick. Default for residential brick.
- Type S — 1800 psi. Below-grade walls, parging, foundation walls, hard freeze-thaw zones.
- Type M — 2500 psi. Heavy load-bearing structures, retaining walls.
- Type O — 350 psi. Interior non-load-bearing only; restoration on historic structures.
Common questions
What's the difference between mortar and concrete?
Mortar is sand + portland cement + lime, designed to bond bricks and have working time. Concrete is sand + portland cement + aggregate (gravel) and designed to be a structural mass. Different products; not interchangeable.
Pre-mixed bag vs masonry cement + sand?
Pre-mixed mortar mix is foolproof — add water, mix, lay. Masonry cement + sand is cheaper if you're laying enough to justify mixing your own (ratio is typically 1 part masonry cement to 2.5–3 parts sand for Type N). For under 500 bricks, just buy pre-mixed.
How long does mixed mortar stay workable?
About 90 minutes once water is added — less in hot/dry weather. You can re-temper (add a little water and re-mix) once during that window, but never twice. Don't try to save mortar overnight.
Pair with the brick calculator to size your wall and the sand calculator for mason sand if you're mixing your own.