Range Hood CFM Calculator
Kitchen hood size by cooktop width and type.
Enter your values
Enter the cooktop width in in.
Choose one of: Electric / induction, Gas.
Enter the total burner btu (gas) in BTU/h.
Choose one of: Against wall, Island / peninsula.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- 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
At a glance
| What it does | Kitchen hood size by cooktop width and type. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Cooktop width, Fuel, Total burner BTU (gas), Hood position |
| Main output | Recommended hood |
| Formula | CFM = cooktop width (ft) x 100 x island factor |
| Cost | Free — no sign-up, no download |
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.
Inputs explained
- Cooktop width(in)
- Enter the cooktop width in in.
- Fuel
- Choose one of: Electric / induction, Gas.
- Total burner BTU (gas)(BTU/h)
- Enter the total burner btu (gas) in BTU/h.
- Hood position
- Choose one of: Against wall, Island / peninsula.
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.
What do I need to enter into the Range Hood CFM Calculator?
Just 4 values: cooktop width, fuel, total burner btu (gas), hood position. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Range Hood CFM Calculator work out the 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. It applies the formula CFM = cooktop width (ft) x 100 x island factor and shows the working so you can check each step by hand.
Is the Range Hood CFM Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.