Chimney Brick Calculator
Enter your chimney’s width and height (and subtract any openings) to get the exact number of bricks and mortar bags to order.
Total area of doors, windows or other openings to subtract.
Covers cuts, breakage and layout waste. 5–10% is normal.
Everything is calculated in your browser. Nothing you type is sent anywhere or stored.
Ordering tips
—
Coverage & waste
Material profile
Brick count comes from the chimney’s face area: width times height, minus any flue openings or cleanout doors, then increased by a waste percentage for cuts and breakage. That net area is divided by the coverage of a single brick, based on its size and a standard mortar joint, to get the total brick count. Mortar bags are estimated from the same net area using a standard coverage rate per bag.
Chimney Brick Sizes and Coverage
Different brick sizes cover different amounts of chimney face per square foot, which changes both your brick count and your mortar joint count.
| Brick Type | Nominal Size (L x H x W) | Coverage (bricks per sq ft) |
|---|---|---|
| Standard modular | 8 x 2.25 x 3.625 in | ~8.6 bricks/sq ft |
| Queen size | 9.625 x 2.75 x 3 in | ~7.4 bricks/sq ft |
| Utility brick | 11.625 x 3.625 x 3.625 in | ~4.5 bricks/sq ft |
Brick coverage by size
| Type | Coverage / unit | Size | Best for |
|---|---|---|---|
| Standard modular brick | 0.116 sq ft | 3.625 x 2.25 x 8 in | Most common chimney brick |
| Queen size brick | 0.135 sq ft | 3 x 2.75 x 9.625 in | Fewer joints, modern look |
How to calculate how many bricks you need
- Measure the chimney’s width and height for each visible face.
- Subtract any flue openings or cleanout doors from the gross area.
- Add waste typically 10%, to cover cuts and breakage on the exposed corners.
- Divide the net area by the brick’s coverage rate and round up to a whole brick.
Worked example
An 8 ft wide, 15 ft tall chimney face with no openings, using standard modular brick and 10% waste:
- Chimney dimensions8 x 15 ft
- Gross face area120 sq ft
- Net area (after openings)120 sq ft
- Waste allowance10%
- Bricks needed1,138 bricks
- Mortar bags needed9 bags
- Brick cost$853.50
- Total material cost$961.50
Chimney Brick Sizes and Coverage
| Brick Type | Nominal Size (L x H x W) | Coverage (bricks per sq ft) |
|---|---|---|
| Standard modular | 8 x 2.25 x 3.625 in | ~8.6 bricks/sq ft |
| Queen size | 9.625 x 2.75 x 3 in | ~7.4 bricks/sq ft |
| Utility brick | 11.625 x 3.625 x 3.625 in | ~4.5 bricks/sq ft |
Ordering Brick and Mortar for a Chimney
Brick is typically sold and delivered by the cube, with roughly 500 standard modular bricks per cube (fewer for larger brick types). For a chimney rebuild or repair, round your brick count up to the nearest full cube where possible to avoid a partial-cube handling fee, and order a few extra bricks beyond your waste allowance in case of breakage during the job or future repairs where a color match matters.
- Order by the cubefull cubes are usually cheaper per brick than a partial-cube pull, and most yards charge extra to break one open.
- Match your mortar typeuse Type N mortar for above-roofline chimney work in most climates, and Type S below grade or in high-exposure areas.
- Keep a few bricks in reservehold back 10 to 20 spare bricks after the job for future tuckpointing or storm damage repair, since brick runs and colors change over time.
- Confirm flue liner and cap separatelythis calculator only covers structural brick, not the flue liner, chimney cap, or crown, which are priced and ordered separately.
Common mistakes
- Forgetting to subtract flue openingscleanout doors and flue openings reduce the net brick area and should be entered separately from the gross face dimensions.
- Skipping the waste allowancechimney brick sees more cuts and breakage than a flat wall due to corners on all four sides, so 10% is a reasonable minimum.
- Buying mortar by the bag without checking coveragemortar coverage varies by joint thickness and brick size, so confirm the bag’s coverage rate against your actual joint width.
- Ignoring the chimney crown and flashingnew brick with a cracked old crown or damaged flashing just moves the water problem, it doesn’t fix it.
What this calculator assumes
Adjust your result if your project differs from these.
- Chimney face is measured as a simple width times height rectangle.
- Openings (flue, cleanout doors) are entered as a total square footage and subtracted from the gross area.
- A single waste percentage covers cuts and breakage across the whole job.
- Mortar bag coverage is based on a standard 3/8 in joint thickness.
- Flashing, crown, cap, and liner materials are not included in this estimate.
Common questions
How do I measure a chimney's face area?
Multiply the width by the height of each visible face, then subtract any flue openings, cleanout doors, or cricket areas.
How much waste should I add for chimney brick?
10% is a solid default. Chimneys have exposed corners on all sides, which increases cutting and breakage compared to a flat wall.
What's the difference between modular and queen size brick?
Queen size bricks are slightly larger, which means fewer bricks and fewer mortar joints per square foot, giving a slightly different look.
How many mortar bags do I need per square foot?
This varies by joint thickness and brick size, but the calculator estimates it from your net brick area using a standard coverage rate.
Does this calculator include the chimney cap or crown?
No. Structural brick and mortar only. Cap, crown, flashing, and flue liner are separate materials priced on their own.
Embed this calculator
Related calculators
Chimney Brick Calculator Estimate
—
materialcalculate.com/tools/chimney-brick-calculator/
Project
| Wall size | — |
| Openings deducted | — |
| Net area | — |
| Material | — |
| Waste allowance | — |
Shopping list
| Units needed | — |
| Mortar / mix | — |
| Estimated total cost | — |
Notes
Estimate generated by materialcalculate.com. Confirm quantities with your supplier before ordering.