Updated September 15, 2026. This guide explains preliminary sizing; the cooking appliance instructions and installation design determine the final selection.
How many CFM should a range hood have?
Start with the cooking appliance's ventilation instructions, the width of the cooking surface and whether it sits against a wall or on an island. Then have the hood and duct system checked together. There is no single CFM number that is right for every kitchen of the same floor area.
CFM means cubic feet per minute, a measure of airflow. It is not electrical wattage, and a bigger number alone does not establish better capture, quieter operation or a suitable installation.
A starting calculation for wall and island installations
HVI recommends 100 CFM per linear foot of range width for a wall location and 150 CFM per foot for an island. The table applies those guidelines. These are preliminary recommendations, not a universal building-code minimum. For pro-style cooking equipment, HVI directs buyers to the cooktop manufacturer's requirements. Source: HVI ventilation sizing guide.
| Cooking width | Wall guideline | Island guideline |
|---|---|---|
| 30 inches / 2.5 feet | 250 CFM | 375 CFM |
| 36 inches / 3 feet | 300 CFM | 450 CFM |
| 48 inches / 4 feet | 400 CFM | 600 CFM |
For example, a 36-inch wall range gives a preliminary target of 3 × 100 = 300 CFM. If its manufacturer specifies a different ventilation arrangement, use those instructions in the design review. Do not buy a hood solely because its maximum rating exceeds the table value.
Gas, electric and induction: use the actual appliance requirements
Write down the exact cooktop or range model before shopping for the hood. Fuel type is useful context, but it does not resolve the required width, installation height or ventilation arrangement by itself. A pro-style gas range and a conventional electric range can have very different instructions.
Rules such as “one CFM per square foot of kitchen,” “room volume divided by four” or “total BTU divided by 100” should not be treated as a complete design for every cooking appliance. A formula that omits the appliance instructions, hood configuration and duct system leaves essential questions unanswered.
Is 400 CFM or 600 CFM enough?
Either can be a candidate when the exact model satisfies the appliance and installation requirements. Neither rating is a blanket approval for all ranges. These two under-cabinet models show why airflow and duct fit need to be considered together:
| Model | Published maximum | Round duct size |
|---|---|---|
| Forno Bari FRHUC5255-30 | 400 CFM | 6 inches |
| ZLINE 623-30 | 600 CFM | 7 inches |
Sources: Forno Bari specifications, Forno manual and ZLINE 623-30 specifications. These examples are under-cabinet hoods; the island sizing column above does not make them island models.
Why ductwork matters to CFM
A fan rating is not a guarantee of the airflow delivered through any possible duct route. Review the outlet size, duct material, route length, bends and termination with the installer. Do not try to compensate for an unsuitable route by adding an arbitrary percentage to the advertised CFM.
The ZLINE 600 Series manual recommends rigid metal ductwork, limits the route and elbows, and warns against reducing below the model's 7-inch transition size. Those are instructions for that series, not dimensions to apply to every hood. Source: ZLINE 600 Series manual.
Have the installer compare the hood's documented performance with the proposed system. If the existing duct is unsuitable, price the correct route before choosing between hoods.
How should you compare advertised airflow?
Check what the number represents. Hauslane's UC-PS18 listing separates a 500 CFM laboratory rating from an 860 CFM equivalent-airflow claim. Two headline numbers with different labels are not automatically comparable measurements. Source: Hauslane UC-PS18 rating information.
Record the rating method and available sound data beside each model. Our range hood brand guide explains how to turn those details into a shortlist.
Do you need make-up air?
Ask the installer to evaluate replacement air as part of the ventilation design, including other exhaust equipment and any fuel-burning appliances in the home. The Forno manual specifically requires attention to sufficient air and prevention of backdrafting. Applicable requirements must be checked for the actual installation with the local authority. Source: Forno Bari installation safety requirements.
Do not assume that buying below a particular advertised CFM number automatically resolves the question. Confirm the complete design before ordering or changing a blower setting.
Does a ductless hood need more CFM?
Increasing recirculating airflow does not create an outdoor exhaust path. HVI notes that recirculating hoods return air to the room and do not remove cooking moisture. There is no universal extra-CFM percentage that makes them equivalent to outdoor ventilation. Source: HVI kitchen ventilation guidance.
Your range hood sizing checklist
- Record the range or cooktop model and obtain its ventilation instructions.
- Measure the cooking width, hood space and intended mounting location.
- Use a preliminary airflow guideline only where appropriate for that appliance.
- Have the installer review the hood, duct route, clearances and replacement-air needs together.
- Compare compatible models by operating controls, cleaning access, support and installed price.
Browse range hoods and send your model number and measurements through our free online appliance fit check. If you need help identifying the equipment itself, read range hood versus exhaust fan.
