Brick Fireplace Calculator — Firebox & Surround
Estimate firebrick for the firebox and face brick for the surround of a residential masonry fireplace. Covers standard Rumford and straight firebox designs.
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 fireplace combines two materials with different heat ratings — refractory firebrick lining the firebox where flame contacts the masonry, and standard face brick on the surround and chimney exterior. Estimating both correctly avoids ordering shortages mid-build and prevents thermal failure later.
This calculator handles the surround and chimney face brick; firebrick is estimated as a separate line item below. Always pair with IRC Chapter 10 (Chimneys and Fireplaces) or engineered drawings for code compliance.
How to Estimate a Brick Fireplace
Face brick = Surround Area × 6.86 + Chimney Area × 6.86. Firebrick = Firebox Surface Area × ~7. Round both up to whole pieces and add 10% waste for cuts.
Fireplace Material Quick Reference
- Standard firebox (36×28×28 in): ~100 firebrick + ~50 lb refractory mortar.
- Surround face brick: 8 ft tall × 5 ft wide ≈ 40 sq ft × 6.86 = ~275 face brick.
- Chimney exterior: 4-sided x ~6 sq ft per vertical foot. A 30 ft chimney = ~720 face brick.
- Through-roof flashing: step-flashing along sides + cricket on uphill side per IRC.
- Lintel: 3-1/2 × 3-1/2 × 1/4 inch angle iron minimum across the firebox opening.
Frequently Asked Questions
What is the difference between firebrick and face brick?
Firebrick (refractory brick) is denser and rated for 2500-3000 °F — required for the firebox interior where flame contacts the masonry. Face brick is standard clay brick rated for ~1800 °F and used for the surround and chimney exterior only.
How many firebrick are in a fireplace firebox?
A standard 36 inch wide × 28 inch deep × 28 inch tall firebox uses approximately 90-120 firebrick depending on layout. The back wall (slope-front) needs the most courses; sides and floor add the rest.
What mortar do I use for firebrick?
Use refractory mortar (sodium silicate or alumina-silicate based) for the firebox interior — Type N or S Portland mortar will fail under repeated thermal cycling. The chimney surround and external face brick use standard Type N mortar.
Do I need a permit for a brick fireplace?
Yes — masonry fireplaces are structural and code-regulated (IRC Chapter 10). Always pull a permit, follow the prescriptive design in IRC R1001 (or engineered drawings), and schedule inspections at footing, throat, and final.
How much does a brick fireplace cost?
Materials only: $2,500-$5,000 for a typical masonry fireplace (firebrick + face brick + flue + damper + lintel). Add $5,000-$15,000 for masonry labor. Prefab metal fireplaces with brick veneer surround are significantly cheaper.
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 →