Free tool: Division 04 masonry
CMU block calculator: blocks, mortar and grout fill
Turn a wall into blocks to order, bags of mortar and cubic yards of grout, using published masonry figures. Add your own prices for the cost per square foot.
Fixed price in 2 business hours. Pay only after you accept.
- Fixed price agreed before any work starts
- Plan review is free
- You pay only after you accept the price and delivery date
- Single-trade estimates in 48 hours
Quick answer
The Bidmere CMU block calculator turns wall length, height and openings into 8 x 16 in blocks at 1.125 per SF plus waste, mortar bags from published blocks-per-bag figures, and grout by wall thickness and grouted cell spacing from CMHA TEK 04-02A. Enter your own prices for a cost per square foot. It is free and runs in your browser.
Division 04: Concrete masonry
CMU block calculator
Blocks, mortar bags and grout fill for a concrete block wall, with openings deducted and grout by cell spacing. Price it at your own block, mortar, grout and labor rates.
Results
Bidding a commercial job? Send the plans and get a measured takeoff
Get a fixed quote Fixed price in 2 business hours. Plan review is free. Pay only after you accept.Need the whole job measured? This calculator covers one area at a time. Send the plans and we return the full takeoff and estimate. Fixed quote within 2 business hours. Plan review is free, and you pay only after you accept.
Get a fixed quoteHow to use the CMU block calculator
- Wall. Length and height in feet, and the openings you deduct.
- Block. 8 x 16 in nominal face, or your own units per square foot for other sizes, plus waste.
- Mortar and grout. The mortar product, the wall thickness and the grouted cell spacing from the structural notes.
- Your costs. Block, mortar bag, grout per cubic yard, labor per square foot and a lump sum.
Run each wall type separately: an 8 in wall grouted every 48 in and a 12 in wall grouted solid are different lines.
How the block calculator works
| Step | Formula |
|---|---|
| Net wall area | Length x height - openings |
| Blocks | Net area x 1.125 per SF x (1 + waste), rounded up |
| Mortar bags | Blocks / blocks per bag, rounded up |
| Grout (CF) | Net area / 100 x grout per 100 SF from the table |
| Grout (CY) | Grout CF / 27 |
| Cost per SF | Total cost / net wall area |
A standard 8 x 16 in unit shows 8/9 SF of face in the wall, so a square foot takes 1.125 units. With the 5% allowance for waste and breakage that CMHA TEK 04-02A uses, that is 119 units per 100 SF.
Mortar calculator: how many bags for block?
| Mortar product (80 lb bag) | Blocks per bag | Source |
|---|---|---|
| Preblended mortar, face shell bedding | About 16 | CMHA TEK 04-02A, Table 2 |
| Quikrete Mortar Mix (Type N) | 12 | Quikrete data sheet No. 1102 |
| Quikrete Mason Mix (Type S) | Up to 13 | Quikrete data sheet No. 1136 |
The TEK figure assumes face shell bedding for conventional block; the Quikrete figures are for standard 8 x 8 x 16 in block. Use the figure for the mortar you will buy. For 1,182 blocks at 16 per bag, order 74 bags; at 12 per bag, 99 bags.
Block fill calculator: grout by cell spacing
Grout volume depends on the wall thickness and how often cells are grouted. These are CMHA TEK 04-02A figures in cubic feet per 100 SF of wall, for two-core units with 3% waste included.
| Grouted cells every | 6 in wall | 8 in wall | 10 in wall | 12 in wall |
|---|---|---|---|---|
| 8 in (solid) | 25.6 | 36.1 | 47.0 | 58.9 |
| 16 in | 12.8 | 18.1 | 23.5 | 29.5 |
| 24 in | 8.6 | 12.1 | 15.7 | 19.7 |
| 32 in | 6.4 | 9.1 | 11.8 | 14.8 |
| 48 in | 4.3 | 6.1 | 7.9 | 9.9 |
Example: 1,000 SF of 8 in wall grouted every 48 in takes 10 x 6.1 = 61 CF, or 2.26 CY. Grouted solid it takes 361 CF, or 13.37 CY. Bond beams and lintels add grout beyond these figures.
What this CMU calculator does not cover
- Bond beams, lintels and their grout and reinforcing
- Vertical and horizontal reinforcing; use the rebar calculator for bar weight
- Joint reinforcement, ties and anchors
- Half blocks, corner and bullnose units by count
- Scaffolding, cleaning and sealers
- Brick or stone veneer
For the bars in the grouted cells, use the rebar calculator. A plan-based masonry takeoff measures each wall type from the elevations and structural notes; see masonry estimating.
Before you send plans
Common questions about handing off the work
Where do the defaults come from?
CMHA TEK 04-02A and Quikrete data sheets, listed under Sources.
Can I bid from these numbers?
For one wall, maybe. A building needs every wall type, bond beam and lintel measured.
Who sets the final price?
You do. Bidmere prices quantities at your rates.
Questions
Frequently asked questions
How many blocks are in 100 square feet?
An 8 x 16 in nominal block covers 8/9 SF, so 100 SF takes 112.5 blocks. CMHA TEK 04-02A adds 5% for waste and breakage, which gives 119 blocks per 100 SF.
How many bags of mortar do I need for block?
CMHA TEK 04-02A gives about 16 conventional blocks per 80 lb bag of preblended mortar with face shell bedding. Quikrete lists 12 blocks per 80 lb bag of its Type N Mortar Mix and up to 13 for its Type S Mason Mix.
How much grout does a CMU wall need?
It depends on thickness and cell spacing. CMHA TEK 04-02A gives 6.1 CF per 100 SF for an 8 in wall grouted every 48 in and 36.1 CF per 100 SF grouted solid, for two-core units with 3% waste.
How do I calculate CMU block for a wall?
Multiply length by height, subtract openings, multiply by 1.125 blocks per SF for 8 x 16 units, add waste and round up. A 100 by 10 ft wall with 5% waste takes 1,182 blocks.
Does the calculator store what I enter?
No. It runs in your browser and does not send or save your entries.
Can Bidmere take off my masonry?
Yes. Send the plans for a free plan review and a fixed quote within 2 business hours. Single-trade estimates are from $195 and ready in 48 hours after you accept.
For your website
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You can put the cmu block calculator on your own website for free, for example on a trade association, school or company resources page. Copy the code below into your page’s HTML. It shows the same calculator in a frame that fits phone screens, with a visible “Calculator by Bidmere” credit that links back to this page.
Get a fixed quote
Share the project basics. You get a fixed price and delivery date within 2 business hours. Plan review is free, and you pay only after you accept.
Sources
- CMHA (formerly NCMA) TEK 04-02A, Estimating concrete masonry materials and labor: https://www.cmha.org/?create-tek-pdf=1&filename=TEK+04-02A&post_id=522088
- Quikrete Mortar Mix No. 1102 data sheet: https://www.quikrete.com/pdfs/data_sheet-mortarmix.pdf
- Quikrete Mason Mix No. 1136 data sheet: https://www.quikrete.com/pdfs/spec_data-masonmix.pdf