Mortar Calculator
Mortar quantity for a brick or block wall.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Brick: mortar ft³ = (units ÷ 1,000) × 7
Block: mortar ft³ = (units ÷ 100) × 3
Bags (exact) = mortar ft³ ÷ yield per bag; Bags (recommended) = ⌈ mortar ft³ × (1 + waste) ÷ yield ⌉
Run the calculation to see each step with your own numbers.
1,000 modular bricks, 0.5 ft³/bag yield, 10% waste.
Mortar = 1.0 × 7 = 7 ft³ → order 7.7 ft³ (10% waste)
Bags = 7 ÷ 0.5 = 14 exact → ⌈7.7 ÷ 0.5⌉ = 16 recommended
- 3/8-in mortar joints, face-shell bedding for block, full bedding for brick.
- Pre-blended bagged mortar (Type N or S). Site-batched mortar from masonry cement + sand uses roughly 1 bag cement + 18–27 shovels of sand per ~12 ft³.
- Yield per bag varies by product and mixing water — 0.5 ft³ is a common figure for a 70–80 lb bag.
- Type N or Type S mortar?
- Type N for most above-grade veneer and non-loadbearing work; Type S for below-grade, retaining and structural masonry. The quantity is the same — the calculator counts volume, not the mix.
- How many bags of mortar per 1,000 bricks?
- Roughly 14 for the exact volume at a 0.5 ft³ per bag yield, and about 16 once you add a normal 10–15% for waste. Block uses less — around 3 bags per 100 units.
- Can I mix mortar from cement and sand instead of bags?
- Yes — roughly one bag of masonry cement to 18–27 shovels of sand yields about 12 ft³. The calculator gives the volume you need to hit; the mix is up to you.
Mortar quantities
≈ 7 ft³ of mortar per 1,000 modular brick (3/8-in joint). Brick Industry Association Technical Note 8B. Default 7.0. ≈ 2.5–3.0 ft³ of mortar per 100 standard CMU (face-shell bedding, 3/8-in joint). NCMA TEK 09-01A. Default 3.0.
About the Mortar Calculator
The Mortar Calculator turns a brick or block count into mortar volume and bags. It works from the standard published quantities — about 7 ft³ per 1,000 modular bricks and 3 ft³ per 100 standard blocks with 3/8 in joints — and gives the bag count both exact and waste-adjusted, since mortar is dropped, wasted and thrown out once it stiffens. It counts volume, not the mix design.
What you enter
- Masonry unit
- Number of units
- Mortar yield per bag (ft³) — A 60–80 lb bag of pre-blended mortar mix yields ~0.45–0.55 ft³.
- Waste allowance — Default 10%. Adjust to your own allowance — the exact figure is always shown too.
What you get back
- Mortar volume — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
- Bags of mortar mix — Exact = bags for the exact mortar volume; recommended = whole bags including the waste allowance.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Brick Calculator — Number of bricks for a wall of a given area and brick size.
- Concrete Block Calculator — Number of concrete masonry units (blocks) for a wall of a given area.
- Block Wall Calculator — Blocks, mortar and fill for a concrete block wall.
- Concrete Block Fill Calculator — Grout volume needed to fill the cores of a concrete block wall.
Part of the Masonry calculators.