Block Mortar Calculator
Enter the number of bricks or blocks below to calculate how many bags of mortar will be needed, or how much materials will be needed to mix on-site.
Material Estimate:
Pre-Mixed Mortar
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Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.
How to Estimate Mortar for Block Projects
Follow three easy steps to estimate the amount of mortar mix needed for your concrete block project.
Step One: Estimate Square Footage
Estimate the square footage of the wall by measuring the width and height in feet. Then, multiply the width and height to find the square footage. Try calculating square footage using a calculator if you’re not comfortable doing it by hand.
Step Two: Calculate the Number of Blocks
Next, calculate the number of blocks needed for the project by the number of blocks per square foot. You’ll need roughly 1 1/8 standard blocks per square foot, so multiply the square footage by 1.125 to estimate the total needed. You can also use our block calculator to calculate other block sizes.
Step Three: Estimate Mortar
The final step will be to find the yield of the mortar you’re using and divide the total number of blocks by the yield. The typical 80-pound bag of mortar will yield 12 blocks so you can calculate by dividing the square footage by 12.
| Block Quantity | 60 lb Bags | 80 lb Bags |
|---|---|---|
| 100 blocks | 12 bags | 9 bags |
| 200 blocks | 23 bags | 17 bags |
| 300 blocks | 34 bags | 25 bags |
How to Estimate Mortar for Brick Projects
The same three steps above can be used to estimate mortar for brick projects.
Step One: Estimate Square Footage
Start by estimating the square footage of the brick wall by multiplying the width by the height together.
Step Two: Calculate the Number of Bricks
Then, calculate the number of bricks by multiplying the square footage by the number of bricks per square feet. Our brick calculator can help with this. You’ll need roughly 6.9 modular bricks per square foot, so multiply 6.9 times the square footage to find the number of bricks needed.
Step Three: Estimate Mortar
Finally, estimate the mortar needed by dividing the total number of bricks by the yield of the mix used. On average a mortar mix will yield 36 bricks per 80-pound bag, so divide the total number of bricks by 36 to calculate the bags needed.
| Brick Quantity | 60 lb Bags | 80 lb Bags |
|---|---|---|
| 500 bricks | 19 bags | 14 bags |
| 1,000 bricks | 38 bags | 28 bags |
| 1,500 bricks | 56 bags | 42 bags |
Types of Mortar
Whether you’re using a pre-mixed mortar or mixing on-site, it’s important to understand the various types there are and which is appropriate for your project. Cement to sand ratio ranges from 1 part cement to 3 to 4.5 parts sand, depending on the type of mortar being mixed and the compressive strength desired.
Most mixes also require the use of lime in various proportions as a binding agent, to increase the longevity of the finished product, and to increase the workability of the mix.
Type O
used in above ground applications that are not load-bearing, usually for interior applications, and has a compressive strength of 350psi.
Type N
used in above ground applications that support light loads, usually for chimneys or brick-work, and has a compressive strength of 750psi.
Type S
used in below ground applications for load bearing applications, usually for foundations and retaining walls, and has a compressive strength of 1,800psi.
Type M
used in below ground applications for heavier load bearing applications, usually for foundations to support , and has a compressive strength of 2,500psi.
| Mortar Type | Cement : Lime : Sand Ratio | Compressive Strength |
|---|---|---|
| Type O | 1:2:9 | 350 psi |
| Type N | 1:1:6 | 750 psi |
| Type S | 2:1:9 | 1,800 psi |
| Type M | 3:1:12 | 2,500 psi |
Try our other gravel calculator to estimate the amount of sand needed for your mix.