Fireplace & Chimney Calculator
Size a chimney flue based on the 10:1 fireplace-to-flue area ratio and estimate draft pressure.
Inputs
in
in
ft
Results
Required Flue Area
100.8 sq in
Flue Size
10.04 in
≈ 3 credit cards
Fireplace Opening Area1,008 sq in
Min Chimney Height20 ft
Estimated Draft Pressure0 in w.c.
How to Use This Calculator
- Enter the fireplace opening width and height in inches.
- Input the chimney height in feet (measured from the firebox floor to the top of the flue).
- Select the flue shape (round or rectangular) and material.
- Review the minimum flue area, throat dimensions, and smoke chamber height.
- Verify design compliance with NFPA 211 and local building codes.
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