Range Hood CFM Calculator
Kitchen hood size by cooktop width and type.
Enter your values
ⓘ Live results
Results
- Recommended hood
- 600 CFM
- By cooktop width
- 300 CFM
- By burner BTU
- 600 CFM
- Minimum hood width
- 39 in
- Make-up air needed?
- Yes — most codes require make-up air above 400 CFM
Quick answer
Wall hoods need roughly 100 CFM per linear foot of cooktop for electric and 100 CFM per 10,000 BTU for gas; island hoods need about 50% more.
CFM = cooktop width (ft) x 100 x island factor
How to use the Range Hood CFM Calculator
- 1Measure the cooktop width in inches.
- 2Pick the fuel type and, for gas, add up the burner BTU ratings.
- 3Choose wall or island — island hoods lose air on all four sides.
Worked example
Using the values the calculator loads with:
Inputs
- Cooktop width36 in
- FuelGas
- Total burner BTU (gas)60000 BTU/h
- Hood positionAgainst wall
Results
- Recommended hood600 CFM
- By cooktop width300 CFM
- By burner BTU600 CFM
- Minimum hood width39 in
- Make-up air needed?Yes — most codes require make-up air above 400 CFM
Frequently asked questions
Is 600 CFM too much?
It is fine for a big gas range, but above 400 CFM most codes require a make-up air supply to avoid back-drafting appliances.
Does duct size matter?
Yes — a 600 CFM hood on 6 inch duct will never reach its rating; use 8 or 10 inch.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.