Disclaimer

The calculators and content on ChimneyCalcs.com are provided for general information and planning.

Estimates and sizing/draft guides, not guarantees

Results are deterministic estimates from your inputs, your prices and standard reference conventions (opening area = width × height; round flue ≥ opening ÷ 12, rectangular ≥ opening ÷ 10; A = π·(d/2)²; the 3-2-10 height rule; cost = materials + labor + access, ×(1 + contingency)). Real chimneys and installs vary — verify measurements and figures before relying on them.

Not a bid, not a price or rate index

Cost tools give planning estimates from your own prices, not bids or contracts, and we store no live material or labor rate, no regional cost index, no product catalog and no sweep or mason directory. Cost bands are a labeled sanity guide only. Get itemized written quotes from a CSIA-certified sweep and a licensed, insured mason.

Confirm your dimensions; size up

Sizing and draft tools give planning guides. Confirm your exact flue and opening dimensions, follow NFPA 211, the appliance manufacturer’s instructions and local code, and round flue area up to the nearest standard liner or tile — real flue requirements, draft and clearances vary by appliance, fuel, chimney and roof geometry.

Labeled typicals, not a certified spec

The flue-size rule, standard clay-tile sizes, liner-by-appliance, creosote stages, NFPA 211 inspection levels, clearances and cost bands are labeled published snapshots / planning typicals — confirm against your exact dimensions, the manufacturer’s instructions, local code and a certified professional. Creosote, chimney fire, carbon monoxide, structural and code judgement are a CSIA-certified sweep / licensed mason / NFPA 211 / local-code matter — not engineered here, and never a medical verdict.

Anti-overlap: residential chimney & fireplace sizing, draft & cost only

This site covers residential chimney & fireplace / hearth venting, flue-geometry sizing, masonry-repair, relining, sweep, inspection & installation math only. It is not a general roofing / re-roof / shingle / gutter resource (exteriorcalcs and guttercalcs own the roof envelope — here only the chimney flashing and the chimney itself, never the roof field or gutters); not a general concrete / structural masonry / foundation / driveway / slab resource (cementcalcs — here only the chimney’s masonry: crown, brick, tuckpointing, firebox); not a space heating / furnace / boiler / hydronic / HVAC-load resource (climatecalcs — the fireplace/stove/chimney is a venting & flue-geometry subject, never a whole-home heating load); not a water-heater sizing resource (waterheatercalcs — here only a water-heater’s chimney/vent liner as flue geometry); not a firewood seasoning / cord-economics resource (here only a minor cord-wood / BTU reference line); and not a professional combustion / gas-line / venting / carbon-monoxide diagnosis or code-certification tool.

Not an installation or safety guide

Nothing here is an installation procedure, a combustion / venting verdict, a chimney-fire or carbon-monoxide medical determination, or safety advice. Defer the professional job to a CSIA-certified sweep and a licensed, insured mason, follow the manufacturer’s installation instructions and NFPA 211, and confirm code with your local building department.