Range Hood CFM Calculator (Free)
Use this free calculator to size your kitchen range hood. Enter your cooktop width and fuel type (gas or electric/induction), mount style (wall/under‑cabinet or island), and basic duct details. The tool estimates recommended airflow in CFM (imperial) and m³/h (metric). Always check appliance manuals and local code requirements.
How to use
- Choose units (Imperial or Metric) and fuel type (Gas or Electric/Induction).
- Enter cooktop width (inches or cm). For gas, you can also enter total burner output (BTU or kW).
- Select mount type (Wall/Under‑cabinet or Island) and enter duct length and elbows if known.
- Pick cooking intensity (Light/Normal/Heavy). Click Calculate to see the recommendation.
Worked example
30″ electric cooktop on an island, duct length 10 ft with 2 elbows, cooking intensity Heavy.
- Base (electric): width × 10 = 30 × 10 = 300 CFM
- Island factor (×1.3): 300 × 1.3 = 390 CFM
- Duct & elbows: +10 (length) +50 (2 elbows) = +60
- Heavy cooking: +100
- Total ≈ 550 → rounded to nearest 50 → 550 CFM (≈ 935 m³/h)
Range hood airflow calculator
FAQs
How many CFM do I need for a gas cooktop?
A common rule is ~1 CFM per 100 BTU of total burner output. For example, 60,000 BTU ≈ 600 CFM. Always confirm with the hood and cooktop manuals.
How do I size a hood for electric or induction?
A simple rule is ~10 CFM per inch of cooktop width (≈100 CFM per foot). A 30″ cooktop is about 300 CFM before other factors.
Do island hoods need more airflow?
Yes. Islands see more cross‑drafts, so this tool increases the target by about 30%. Many manufacturers recommend wider hoods and higher CFM for islands.
What about long ducts and elbows?
Longer ducts and 90° elbows add resistance. This tool adds a small allowance per foot and per elbow, but manufacturer guidance should take priority.
Is higher CFM always better?
Higher CFM can be louder and may require make‑up air under some codes above certain thresholds. Balance capture area, noise (sones), and airflow.