Brick Chimney Calculator — Bricks Per Foot of Chimney
Estimate face brick for a residential chimney from grade to cap. Includes step-flashing course allowances and a separate cricket estimate with waste factor.
Enter Dimensions
Standard is 3/8 in (0.375)
Results
Bricks Needed
1,207bricks
Mortar Bags (60 lb)
35bags
Type S mortar, ~35 bricks/bag
Wall Area
160sq ft
Bricks per Sq Ft
6.86bricks/sq ft
Editorial Standards
Each calculator is reviewed for formula accuracy, unit consistency, and alignment with current U.S. building practices before publication. We verify outputs against published engineering references and real-world project data. Learn more about our methodology.
A brick chimney is a tall, narrow masonry assembly with strict code requirements: IRC R1003 governs fire safety, flue sizing, clearances from combustibles, and roof termination height (the "3-2-10" rule). Material estimating is straightforward once you know the cross-section: perimeter ÷ 8 = bricks per course.
This calculator estimates face brick for the chimney exterior. Add firebrick (for the firebox) and clay flue tile separately — both are mandatory and not included in face-brick counts.
How to Estimate a Brick Chimney
Bricks per course = Perimeter (in) ÷ 8 in. Total bricks = (Perimeter ÷ 8) × (Chimney Height in feet × 4 courses/ft) × (1 + waste %).
Chimney Cross-Section Reference
- Single-flue, 16×20 inch: 9 bricks/course × 4 courses/ft = 36 bricks per LF.
- Single-flue, 20×24 inch: 11 bricks/course = 44 bricks per LF.
- Double-flue, 16×32 inch: 12 bricks/course = 48 bricks per LF.
- 30 ft chimney: ~1080 bricks for the 16×20 single-flue case.
- Flue tile: 1 × 24-inch tile per 2 ft chimney height.
- Mortar: 1 bag Type N per 30 bricks (NCMA).
Frequently Asked Questions
How many bricks per linear foot of chimney height?
Depends on chimney cross-section. A 16×20 inch single-flue chimney (typical residential): perimeter 72 inch = 6 LF per course × ~4 courses per foot height = ~25 bricks per linear foot of chimney height.
What size flue do I need?
Per IRC R1003 / NFPA 211: round flue area = ~1/12 to 1/10 of fireplace opening. For a 36×28 inch fireplace opening (1008 sq in): flue area ≥ 84-100 sq in. Standard 12×12 inch clay flue tile (~108 sq in) works.
How tall does a chimney need to be?
Per IRC R1003.9: at least 3 ft above the highest roof penetration point AND at least 2 ft taller than any roof point within 10 ft horizontally. The '3-2-10 rule' is the universal benchmark.
How much does a brick chimney cost?
$3,000-$8,000 for materials on a typical 25-30 ft residential chimney. Add $5,000-$15,000 for masonry labor. Rebuilds and tall chimneys with multiple flues push above $20,000 installed.
Do I need flashing for the chimney?
Yes — step flashing on the sides up the roof, plus a cricket (saddle) on the upslope side of any chimney wider than 30 inches. Counter-flashing embedded in mortar joints reglets across the brick face.
Looking for the general calculator?
Calculate bricks and mortar bags for walls, patios, and masonry projects. Supports standard modular, queen, and Norman bricks with adjustable mortar joint size.
Open the Brick Calculator: Bricks & Mortar Bags →