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Range Hood CFM Calculator (Wall & Island)
Last updated: October 26, 2026.
Quick answer: HVI suggests about 100 CFM per foot of range width for a wall hood and 150 CFM per foot for an island hood. For gas ranges, a common rule is total burner BTU ÷ 100. Use the higher number, then check your range and hood manuals. Hoods capable of more than 400 CFM often trigger make-up air rules.
Worked examples
| Scenario | Width method | BTU method | Suggested starting point |
|---|---|---|---|
| 36" wall hood, 60,000 BTU gas | 300 CFM (3 ft × 100) | 600 CFM | 600 CFM (round up as needed) |
| 36" island hood, 60,000 BTU gas | 450 CFM (3 ft × 150) | 600 CFM | 600 CFM |
| 30" wall hood, electric/induction | 250 CFM | n/a | 250 CFM (still confirm manuals) |
| 48" wall hood, 90,000 BTU gas | 400 CFM | 900 CFM | 900 CFM + make-up air review |
Make-up air: If your recommendation is over 400 CFM, IRC M1503.6 may require make-up air where adopted. Ask a licensed installer or your local building department before you buy.
How we calculate
- Width method (HVI): wall hood 100 CFM per linear foot of range width; island hood 150 CFM per foot.
- BTU method (gas): total burner BTU/hr ÷ 100 (Trade-Wind rule of thumb; HVI says pro-style cooktops should follow the manufacturer's recommendation).
- Code floor: IRC kitchen exhaust minimum 100 CFM intermittent — a floor, not a target.
Estimates only. Your range and hood manufacturers' instructions and local code take priority. Hood, duct, gas, and make-up air work should be done by a licensed installer.
Shop hoods after you size CFM
- All range hoods
- Wall mount range hoods
- Island range hoods
- ZLINE hoods and ranges (confirm live stock on each product)
- Related: Range ventilation planning checklist
FAQ
How many CFM do I need for a 36-inch gas range?
A common starting point is HVI's width method (about 300 CFM for a 36-inch wall hood) and the BTU method (total burner BTU ÷ 100). Use the higher number, then check the range and hood manuals.
When is make-up air required?
IRC M1503.6 requires make-up air for kitchen exhaust hoods capable of more than 400 CFM in many homes where that code is adopted. Ask your installer or building department.
Is island hood CFM different from wall hood CFM?
Yes. HVI suggests about 150 CFM per linear foot for island hoods versus about 100 CFM per foot for wall hoods.
Can I use a recirculating hood over a gas range?
Recirculating hoods filter grease but do not remove heat, moisture, or combustion gases (HVI). Prefer ducted exhaust for gas cooking when possible.
Sources (checked Oct 26, 2026)
- HVI, How Much Ventilation Do I Need?
- DOE Building America kitchen ventilation / make-up air fact sheet: osti.gov
- IRC 2021 M1503.6 and Table M1505.4.4
- Trade-Wind, Determining CFM Requirements