Brick Mortar Quantity Calculator
Calculate how much mortar you need per 1000 bricks based on brick size, joint thickness, and mortar type.
Covers both metric and imperial measurements.
Enter the number of bricks and joint size to calculate mortar needed.
Understanding Mortar Quantity for Bricklaying
Mortar is the binding material between bricks that provides structural integrity and weather resistance. The amount of mortar needed depends on the size of the bricks, the thickness of the mortar joints, and the type of bond pattern used. Accurately estimating mortar saves money and reduces waste on construction projects. Mortar typically accounts for about 15 to 20 percent of the total wall volume.
The Basic Formula:
Mortar Volume = Number of Joints x Joint Length x Joint Width x Joint Depth
For practical estimation, the industry standard is to calculate mortar per 1000 bricks.
Mortar Needed per 1000 Bricks by Joint Size:
| Brick Type | Joint Size | Mortar per 1000 Bricks | Bags of Cement |
|---|---|---|---|
| Standard (215 x 102 x 65 mm) | 10 mm (3/8 in) | 0.45 m³ (16 ft³) | 7-8 bags |
| Standard (215 x 102 x 65 mm) | 12 mm (1/2 in) | 0.55 m³ (19 ft³) | 9-10 bags |
| Modular US (194 x 92 x 57 mm) | 10 mm (3/8 in) | 0.50 m³ (18 ft³) | 8-9 bags |
| King size (295 x 100 x 65 mm) | 10 mm (3/8 in) | 0.40 m³ (14 ft³) | 6-7 bags |
| Queen closer (215 x 50 x 65 mm) | 10 mm (3/8 in) | 0.60 m³ (21 ft³) | 10-11 bags |
Mortar Mix Ratios:
Different applications require different mortar strengths. The mix ratio is expressed as Cement : Lime : Sand by volume.
- Type M (1:0.25:3.5): High strength, for below-grade foundations and retaining walls
- Type S (1:0.5:4.5): Medium-high strength, for exterior walls and severe weather exposure
- Type N (1:1:6): Medium strength, general purpose for above-grade exterior and interior walls
- Type O (1:2:9): Low strength, for interior non-load-bearing walls
Waste Factor:
Always add 10 to 15 percent extra mortar to account for waste from dropping, tooling joints, cleaning, and mortar that hardens before use. On large projects, waste can be minimized with careful planning. On small projects with less experienced workers, budget for up to 20 percent waste.
Coverage Estimates:
One standard bag of premixed mortar (80 lb or 36 kg) covers approximately 35 to 40 standard bricks with a 10 mm (3/8 inch) joint. One bag of cement (94 lb or 42.6 kg) mixed with sand at a 1:3 ratio will lay approximately 125 to 140 standard bricks. These estimates assume bed joints and head joints are both filled properly.
Practical Example:
Building a garden wall that is 10 feet long and 4 feet high (3 meters by 1.2 meters) using standard bricks in a stretcher bond requires approximately 600 bricks and 0.27 cubic meters (9.5 cubic feet) of mortar, which is about 4 to 5 bags of cement mixed with proportional sand.