Calculators
Masonry Block Calculator
Calculate concrete blocks and mortar bags for a wall from wall size, block face size, openings and waste.
- Runs in your browser
- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Estimating block for a garden or retaining wall
- Pricing masonry work
- Foundation wall estimates
- Ordering materials
About this tool
What the Masonry Block Calculator does
Block count is the wall area divided by the face area of one block including its mortar joint. A standard 8 × 8 × 16 inch concrete block covers about 0.89 sq ft with a 3/8 inch joint, so a wall needs roughly 1.125 blocks per square foot.
Formula
- Block face area = length × height (with joint) ÷ 144
- Blocks = wall area ÷ face area × (1 + waste)
- Mortar bags = blocks ÷ blocks per bag
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| Wall length | 40 ft |
| Wall height | 6 ft |
| Openings area | 0 sq ft |
| Block length with joint | 16 in |
| Block height with joint | 8 in |
| Waste allowance | 5% |
| Blocks laid per mortar bag | 30 |
| Result | Value |
|---|---|
| Blocks | 284 |
| Mortar bags | 10 |
| Wall area | 240 |
| Courses | 9 |
How to read the result
Retaining and load-bearing walls need engineered reinforcement and grout fill; these are outside a simple block count.
Order corner and half blocks separately if your design needs them.
Quantities are estimates. Check product data sheets and local codes, and confirm with your supplier before ordering.
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Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
About 1.125 standard 8 × 16 inch blocks per square foot of wall.
It depends on the mortar product; manufacturers state how many blocks a bag lays.
Yes, subtract doors and windows from the wall area.
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