How many CFM a range hood needs depends mostly on two things: how wide the cooking surface is and whether it sits against a wall or in an island. The Home Ventilating Institute (HVI) recommends 100 CFM per linear foot of range for a wall hood and 150 CFM per foot over an island, with lower minimums of 40 and 50 CFM per foot. This page turns those rates into a calculator and a chart for 24 to 60 in ranges, and covers hood width, mounting height, ducting and the ENERGY STAR criteria for hoods.
Range hood CFM calculator
Range hood CFM chart by width
| Range width | Wall hood, recommended CFM | Wall hood, minimum CFM | Island hood, recommended CFM | Island hood, minimum CFM |
|---|---|---|---|---|
| 24 in | 200 | 80 | 300 | 100 |
| 30 in | 250 | 100 | 375 | 125 |
| 36 in | 300 | 120 | 450 | 150 |
| 42 in | 350 | 140 | 525 | 175 |
| 48 in | 400 | 160 | 600 | 200 |
| 54 in | 450 | 180 | 675 | 225 |
| 60 in | 500 | 200 | 750 | 250 |
The gap between “recommended” and “minimum” is wide on purpose. The minimum is enough for light cooking: simmering, boiling a pot of pasta, reheating. The recommended rate is for the cooking that fills a kitchen with smoke or steam: searing, stir-frying, frying. HVI notes that hoods with several speed settings let you run quietly at the low end most of the time and turn up the airflow when you need it, so a hood with a top speed near the recommended figure and a quiet low speed covers both.
Why does an island need more? A wall and the cabinets on either side of a wall hood help hold the rising plume of hot air under the canopy. Over an island there is nothing on any side, and drafts from people walking past or a door opening push the plume sideways, so a hood has to pull harder to catch it. HVI’s table puts island hoods at 150 CFM per foot, and for its hood-width chart says to multiply the wall figures by 1.5.
Hood width and mounting height
- Width: HVI says a hood should be at least as wide as the cooking surface it serves. A hood wider than the range, by a few inches each side, catches more of a plume that leans in a draft.
- Height: HVI gives 18 to 30 in above the burners. Lower catches more smoke and steam but crowds tall pots and the cook’s head; higher is more comfortable but lets more escape. The hood maker’s installation instructions, and the range maker’s clearance to combustibles, set the limits for a particular product and take precedence.
- Shape: canopy hoods above the range capture the rising column of air with relatively low airflow, according to HVI. Downdraft exhausters that rise from the counter need more airflow and higher velocity, and HVI says their performance cannot equal a canopy hood over the cooktop; check the range maker’s advice before choosing one.
- Professional-style cooktops: HVI’s per-foot rates are for ordinary household ranges. For a professional-style cooktop, HVI recommends following the cooktop maker’s ventilation requirements, which are often much higher.
Ducted or recirculating
A ducted hood moves the air outdoors. A recirculating (ductless) hood pulls it through a grease filter, often a charcoal filter too, and blows it back into the kitchen. HVI is blunt about the difference: recirculating hoods provide no actual ventilation. They do not remove moisture or combustion products from a gas range, and their value against odours is limited. If there is any way to run a duct to the outside, do it, and use smooth metal duct of the size the hood calls for, with as few elbows as possible.
Large hoods add a second consideration. A hood pulling several hundred CFM out of a tight house has to be replaced by the same volume of air coming in somewhere, and if there is no planned path it can pull air down a chimney or a water heater flue. Many building codes require a makeup air supply for kitchen exhaust above a set airflow, so check the rule where you live before you buy a high-capacity hood.
Ratings to check on the hood
- Certified airflow. HVI warns that inflated airflow claims are common for hoods that are not HVI-Certified. A certified rating is the only one you can compare between brands.
- Sones. Loudness as people hear it; the scale is linear, so 4 sones is twice as loud as 2. ENERGY STAR caps certified range hoods (75 W or less) at 2.0 sones.
- Efficacy. ENERGY STAR range hoods must move at least 2.8 CFM per watt and draw 75 W or less, and must meet the criteria in every possible configuration.
Worked example: 36 in gas range on a wall
The range is 3 ft wide, so the HVI rates give 3 x 100 = 300 CFM recommended and 3 x 40 = 120 CFM minimum. A 36 in hood with a quiet low speed of about 150 CFM and a high speed of about 300 CFM covers both, ducted through the wall behind it. If the same range moves to an island, the figures become 3 x 150 = 450 CFM recommended and 150 CFM minimum, and a hood a size wider than the range, such as 42 in, catches more of a plume that drifts in a draft. At 450 CFM, check whether your code calls for makeup air.
Building codes also regulate exhaust fans, duct termination and makeup air, and they vary by state and city. HVI’s figures are industry guidance; your building department decides what is required on your job.
Related calculators
- Bathroom exhaust fan CFM calculator: exhaust fan size by room area and fixtures
- Whole house fan size calculator: house cooling fans and attic vent area
- ADA counter and sink height: counter and work-surface heights
Frequently asked questions
How many CFM do I need for a range hood?
HVI recommends 100 CFM per linear foot of range for a hood against a wall and 150 CFM per foot in an island; minimums are 40 and 50 CFM per foot. A 30 in wall range: 250 CFM recommended, 100 minimum.
How many CFM for a 36 inch range hood?
300 CFM recommended and 120 CFM minimum against a wall; 450 recommended and 150 minimum in an island (HVI rates).
How high should a range hood be above the stove?
18 to 30 in above the burners, according to HVI, within the limits in the hood and range makers’ instructions.
Should a range hood be wider than the stove?
At least as wide as the cooking surface, according to HVI; a few inches wider helps capture.
Do recirculating range hoods work?
They trap grease, but HVI says nonducted recirculating hoods provide no actual ventilation: they do not remove moisture or combustion products. Vent to the outside where you can.
What CFM range hood for a gas stove?
The HVI per-foot rates apply to household gas and electric ranges alike. For professional-style gas cooktops, follow the cooktop maker’s requirements, which are usually higher.
Sources
- Home Ventilating Institute (HVI), How Much Ventilation Do I Need? (HVI ventilation guide articles; read 25 October 2026). Range hood rates per linear foot, the width table and the island multiplier.
- HVI, Ventilating Living Areas (hood width, 18 to 30 in mounting height, recirculating hoods).
- US EPA, ENERGY STAR, Ventilating Fans Key Product Criteria: minimum efficacy, maximum sound levels and installed performance (read 25 October 2026).
Last reviewed: 25 October 2026. Numbers in the tables are our arithmetic from the sources listed; code sections are summarised, not quoted. How we check our work: methodology and corrections. Spotted an error? Please let us know.