What to measure
How to use the mortar calculator
Enter the wall’s length and height and subtract doors and windows in square feet. Pick the brick size or concrete block, then the mortar: premixed mortar mix in 80 or 60 lb bags, or 70 lb bags of masonry cement that you mix with sand. Keep 5% extra for breakage and cuts.
The count is for a single-wythe wall, one brick or one block thick.
The formula
- Bricks or blocks = wall area × units per sq ft × (1 + extra %), the same counts the brick and block calculators use
- 80 lb mortar mix: bags = bricks ÷ 37, or blocks ÷ 13. A 60 lb bag lays 60/80 as many.
- Masonry cement, brick: 7 bags and 1 ton of sand per 1,000 bricks
- Masonry cement, block: bags = blocks ÷ 46, with 240 lb of sand per bag
Worked example: 20 × 8 ft wall, modular brick
- Bricks: 160 sq ft × 6.86 × 1.05 = 1,152
- 80 lb mortar mix: 1,152 ÷ 37 = 31.1 → 32 bags
- 60 lb mortar mix: 1,152 ÷ 27.75 = 41.5 → 42 bags
- Or masonry cement: 1,152 × 7 ÷ 1,000 = 8.1 → 9 bags, with 1.15 tons of sand
Worked example: 20 × 8 ft wall, concrete block
- Blocks: 160 sq ft × 1.125 × 1.05 = 189
- 80 lb mortar mix: 189 ÷ 13 = 14.5 → 15 bags
- Or masonry cement: 189 ÷ 46 = 4.1 → 5 bags, with about 0.49 tons of sand
Mortar by wall area
80 lb bags of mortar mix or 70 lb bags of masonry cement, 5% extra.
| Wall area | Modular brick, mortar mix | Modular brick, masonry cement | Block, mortar mix |
|---|---|---|---|
| 50 sq ft | 10 bags | 3 bags | 5 bags |
| 100 sq ft | 20 bags | 6 bags | 10 bags |
| 200 sq ft | 39 bags | 11 bags | 19 bags |
| 300 sq ft | 59 bags | 16 bags | 28 bags |
| 500 sq ft | 98 bags | 26 bags | 46 bags |
| 1,000 sq ft | 195 bags | 51 bags | 91 bags |
Where the figures come from
The premix figures are QUIKRETE’s: up to 37 standard bricks or 13 blocks per 80 lb bag. Sakrete’s Type S data sheet rates a little lower, at 35 bricks or 12 blocks, so with Sakrete add a bag or two on a big wall.
For brick laid with masonry cement, this page uses the same rule as the brick calculator: 7 bags of cement and 1 ton of sand per 1,000 bricks. QUIKRETE’s own figure of 144 bricks per bag of masonry cement works out to 6.9 bags per 1,000, so the two agree. Its 240 lb of sand per bag comes to about 0.83 tons per 1,000 bricks, which leaves the 1 ton rule a little sand to spare.
The mortar ratings are per brick, and queen and king bricks are larger than the standard brick the bag ratings assume. Keep the extra at 5% or more for those.
Common mistakes
- Buying mortar by wall area alone. Mortar goes by the number of joints, so a wall of small modular bricks takes more mortar than the same wall in king bricks or block.
- Mixing up masonry cement and mortar mix. Masonry cement is only the binder and needs sand. Mortar mix already has sand in it and needs only water.
- Picking Type N for a foundation or load-bearing wall. Use Type S there. The bag count is the same either way.
- Leaving out parging. The bag ratings cover laying units only. A parge coat on a block wall takes extra mortar on top.
Frequently asked questions
How many bags of mortar for 1,000 bricks?
About 28 bags of 80 lb mortar mix, at 37 bricks per bag. Mixing your own takes about 7 bags of masonry cement and 1 ton of sand. Add 5% or so for waste.
How many bricks does a bag of mortar lay?
QUIKRETE rates its 80 lb Mortar Mix at up to 37 standard bricks or 13 8 × 8 × 16 in blocks. Sakrete rates its 80 lb Type S at 35 bricks or 12 blocks. A 60 lb bag lays about three quarters as many.
How much mortar for a 20 x 8 ft brick wall?
32 bags of 80 lb mortar mix. The wall takes 1,152 modular bricks with 5% extra. With masonry cement it's 9 bags plus about 1.15 tons of sand.
How many bags of mortar for 100 blocks?
8 bags of 80 lb mortar mix, at 13 blocks per bag. With masonry cement it's 3 bags (46 blocks each) and about 520 lb of mason sand.
Type N or Type S mortar?
Type S for load-bearing walls and work below grade, the uses Sakrete sells its Type S for. QUIKRETE's everyday Mortar Mix is Type N. Under ASTM C270, Type S must reach at least 1,800 psi and Type N 750 psi. Both lay the same number of units per bag, so the count doesn't change.
How much sand do I mix with a bag of masonry cement?
QUIKRETE's mix design is one 70 lb bag of masonry cement to 240 lb of mason sand. That makes about 2.75 cu ft of mortar.
Why does this page count fewer blocks than the block calculator?
This page works from wall area, at 1.125 blocks per square foot. The block calculator rounds every course up to whole blocks, so a 10 × 10 ft wall is 126 blocks there and 119 here. Both come to 10 bags of mortar mix.
Sources
- QUIKRETE — Mortar Mix data sheet (37 bricks or 13 blocks per 80 lb bag; ASTM C270 strengths)
- QUIKRETE — Mason Mix (Type S) spec data
- QUIKRETE — Masonry Cement data sheet (70 lb bag + 240 lb sand lays 46 blocks or 144 bricks)
- Sakrete — Mortar Mix Type S data sheet (35 bricks or 12 blocks per 80 lb bag)
- Frederick Block — estimating rules (masonry cement and sand per 1,000 bricks)
Formulas and defaults last reviewed October 30, 2026. How we check our math.