Looking for a quick answer on how much CFM your range hood needs? The chart below gives you a starting point based on your stove type. But don't stop there — the number from this chart is a minimum baseline, and hitting that baseline alone won't guarantee a smoke-free kitchen.
This guide walks you through the standard BTU-to-CFM calculation, then explains what the chart can't tell you: why real-world CFM is always lower than the spec sheet, what factors actually determine whether your hood keeps the air clean, and how to evaluate range hoods beyond a single number.
Range Hood CFM Chart by Stove Type
The most widely used rule for gas stoves is 1 CFM per 100 BTU of total burner output. For electric and induction cooktops, there's no BTU equivalent, so recommendations are based on cooking intensity.
| Stove Type | Typical BTU Range | Minimum CFM | Notes |
|---|---|---|---|
| Electric cooktop (coil or smooth-top) | N/A (watts) | 200–400 CFM | Less combustion gas; ventilation mainly handles steam and odors |
| Induction cooktop | N/A | 200–400 CFM | Cleanest heat source; moderate ventilation sufficient |
| Standard gas cooktop (4 burners) | 30,000–48,000 BTU | 300–480 CFM | 1 CFM per 100 BTU baseline |
| High-output gas cooktop (5–6 burners) | 48,000–75,000 BTU | 480–750 CFM | Multiple high-BTU burners running simultaneously |
| Professional gas range | 75,000–120,000+ BTU | 750–1,200 CFM | Commercial-grade heat needs serious ventilation capacity |
| Wok burner (single, high-flame) | 20,000–30,000 BTU | 600–900 CFM | Intense heat + oil splatter creates dense grease plumes beyond what BTU calc predicts |
Not sure about your BTU output? Check the spec plate on the back or underside of your cooktop, or search the model number on the manufacturer's site.
The BTU-to-CFM Formula
Total BTU ÷ 100 = Minimum CFM
A 4-burner gas cooktop rated at 48,000 BTU needs at least 480 CFM. This formula is endorsed by the Home Ventilating Institute (HVI) and most range hood manufacturers as a reasonable starting point.
But that's all it is: a starting point. Here's why the chart doesn't tell the full story.
Why the CFM Number on the Box Is Misleading
Every CFM chart you'll find online (including this one) uses the manufacturer's rated CFM. The problem is that this number is measured under ideal lab conditions with zero static pressure — no ductwork, no bends, no resistance.
In your actual kitchen, several factors reduce the real airflow:
Ductwork Losses
According to the DOE Building America duct guide, ductwork significantly affects delivered airflow:
- Each 90-degree elbow adds the equivalent of 5–10 feet of straight duct in resistance
- Runs over 15 feet or with multiple bends can cut real-world CFM by 25–40%
- Flex duct (corrugated) creates even more friction than smooth rigid metal — it should never be used for range hood exhaust
- Backdraft dampers and wall/roof caps add further resistance
Environmental Factors
Things you'd never think of also affect airflow:
- Open windows or doors create cross-drafts that compete with the hood's suction
- People walking through the kitchen generate air movement that disrupts the capture zone
- Kitchen layout — an open floor plan lets air currents from HVAC vents, fans, and adjacent rooms interfere with the hood
- Altitude and temperature affect air density, which changes effective airflow
The Bottom Line on CFM Ratings
A hood rated at 900 CFM might deliver 550–700 CFM in your kitchen. A hood rated at 600 CFM with shorter, straighter ductwork might deliver the same real-world airflow. The spec sheet number is not the number you actually get.
CFM by Kitchen Size: A Secondary Check
Some installers use kitchen volume as a cross-reference. The formula, based on ASHRAE 62.2 ventilation principles:
(Kitchen sq ft × Ceiling height × 15) ÷ 60 = CFM
The "15" represents 15 air changes per hour, a common benchmark for kitchens with gas cooking.
| Kitchen Size | Ceiling | Volume | CFM for 15 ACH |
|---|---|---|---|
| 80 sq ft (small galley) | 8 ft | 640 cu ft | 160 CFM |
| 120 sq ft (standard) | 8 ft | 960 cu ft | 240 CFM |
| 200 sq ft (large kitchen) | 9 ft | 1,800 cu ft | 450 CFM |
| 300 sq ft (open plan) | 9 ft | 2,700 cu ft | 675 CFM |
Use whichever method (BTU or room volume) gives the higher number as your minimum baseline.
The 400 CFM Threshold: Makeup Air Requirements
If your range hood exceeds 400 CFM, most U.S. building codes (per IRC Section M1503.6) require a makeup air system. A powerful exhaust hood creates negative pressure that can:
- Backdraft gas water heaters, furnaces, or fireplaces
- Pull radon, sewer gas, or garage fumes into the home
- Make exterior doors difficult to open
A makeup air damper opens automatically when the hood runs, letting fresh air in at roughly the same rate. Factor $500–$2,000+ for this if you're planning a hood above 400 CFM. This is another hidden cost of the "more CFM is better" approach — higher rated hoods trigger code requirements and installation complexity that a better-engineered hood with more focused airflow can avoid.
What the CFM Chart Can't Tell You
Here's the fundamental limitation: CFM measures how much air moves, not how well your hood captures cooking pollutants. Two hoods with identical CFM ratings can have wildly different real-world performance based on factors that don't appear in any chart.
Air Velocity: Speed vs. Volume
Air velocity — how fast air moves at the intake, measured in meters per second (m/s) — determines capture effectiveness far more than total volume. The physics is simple: velocity = airflow ÷ intake area. A narrower, focused intake achieves higher velocity with less total airflow.
Think of it as a garden hose versus a pressure washer. Both use water, but the pressure washer cleans your driveway because the speed of the water does the work, not the volume. A range hood works the same way: high-velocity intake creates a focused suction zone that locks grease and smoke at the source, while a high-volume, low-velocity hood lets fine particles escape sideways.
Traditional range hoods achieve intake velocities of 3–5 m/s. High-velocity designs reach 13–16 m/s — three to five times faster. At those speeds, even PM2.5 particles and cooking odors are captured before they spread. The EPA warns that cooking can push indoor particulate levels above outdoor air quality standards, making effective capture — not just air movement — critical for health.
Capture Efficiency: The Spec That Matters Most
Capture efficiency measures the percentage of pollutants that actually enter the hood rather than escaping into the room. A hood with 95% capture efficiency at 500 CFM will keep your kitchen cleaner than a hood with 60% efficiency at 1,000 CFM.
Capture efficiency depends on intake velocity, hood geometry, proper sizing, mounting height, and anti-escape features like air curtains. None of these appear in a CFM chart.
Performance Decay
Traditional high-CFM hoods often suffer from performance decay: the fan starts strong but as grease accumulates on filters and blades, effective airflow drops. Some hoods lose noticeable suction after extended high-heat cooking in a single session. Hoods engineered for sustained high velocity avoid this by using aerodynamic separation instead of brute-force suction.
How to Actually Choose a Range Hood (Beyond the Chart)
Use the CFM chart above to establish your minimum baseline. Then evaluate hoods on these additional factors:
- Intake velocity. Does the manufacturer publish air speed specs in m/s? Anything above 10 m/s indicates serious engineering; 13+ m/s is exceptional.
- Capture demonstration. Can you see the hood working in a real cooking scenario? Video demonstrations with visible smoke are worth more than a CFM number.
- Noise at your daily speed. Check sones ratings at medium, not just minimum. You'll run medium speed 80% of the time.
- Maintenance requirements. Mesh and baffle filters need cleaning every 2–4 weeks. Filter-free designs using centrifugal or vortex separation eliminate filters entirely.
- Ductwork compatibility. Measure your duct run length and count the elbows. If you have a complex duct path, a hood that achieves effective capture through velocity rather than volume will lose less performance to duct resistance.
- Build quality. 304 stainless steel is more durable and corrosion-resistant than 430. Check motor warranty length as a proxy for manufacturer confidence.
For the full buying framework, see our complete range hood buying guide.
Real-World Sizing Example
Let's walk through a real scenario. You have a 36-inch gas cooktop rated at 48,000 BTU, in a 200 sq ft kitchen with 9-foot ceilings, and your ductwork runs 12 feet with two 90-degree elbows.
Step 1: BTU calculation
48,000 ÷ 100 = 480 CFM minimum
Step 2: Room volume cross-check
(200 × 9 × 15) ÷ 60 = 450 CFM
Step 3: Take the higher number
480 CFM is your baseline.
Step 4: Consider ductwork losses
Two 90-degree elbows add the equivalent of 10–20 feet of duct, plus the 12-foot run. You could compensate by picking a hood rated 20–30% higher (576–624 CFM) — or you could pick a hood engineered for high intake velocity that performs well even with duct resistance, because the focused airflow is less affected by back-pressure than diffuse high-volume flow.
The traditional advice would be "buy a 600 CFM hood." The smarter approach: buy a hood that meets your baseline and achieves high intake velocity with strong capture efficiency. You'll get better results with less noise and lower energy use.
Arspura's Approach: Velocity Over Volume
Arspura's IQV (Intelligent Quad-Vortex) technology is designed around this exact principle. Instead of chasing higher CFM numbers, IQV hoods generate intake velocities of 13–16 m/s through four engineered vortex channels that create a focused low-pressure capture zone.
The practical results:
- Capture at the source — smoke and grease are intercepted before they can escape, even during heavy wok cooking or high-heat frying
- A "golden triangle" clean-air zone between the cook and the hood, kept clear by an anti-escape air curtain that blocks forward drift
- Consistent performance without the velocity decay that traditional hoods experience under sustained load
- Filter-free operation — grease is separated by centrifugal force within the vortex, not by disposable or washable filters
Explore the technology in depth in our range hood technology guide, or see how velocity-first engineering compares to traditional approaches in our air velocity vs. CFM breakdown.
Frequently Asked Questions
How many CFM do I need for a 30-inch gas range?
Most 30-inch gas ranges output 40,000–55,000 BTU total, giving a baseline of 400–550 CFM. But this is a minimum — actual kitchen performance depends on your ductwork, hood design, and intake velocity. A hood with focused high-velocity intake at 500 CFM can outperform a traditional hood at 800 CFM.
How many CFM do I need for a 36-inch range?
A 36-inch range typically has 5–6 burners pushing 55,000–75,000 BTU, giving a baseline of 550–750 CFM. See our range hood sizing guide for detailed sizing logic.
Is 400 CFM enough for a gas stove?
For a standard 4-burner gas cooktop under 40,000 BTU with short, straight ductwork, 400 CFM meets the baseline — especially if the hood has high intake velocity and strong capture efficiency. If you're relying on CFM alone with a traditional low-velocity hood, you may find 400 CFM insufficient for heavy cooking.
What happens if my range hood CFM is too low?
Lingering smoke, grease film on cabinets and ceilings, persistent cooking odors, and elevated indoor levels of PM2.5 and nitrogen dioxide from gas combustion. The EPA notes that cooking is one of the most significant sources of indoor particulate pollution.
Is the 1:100 BTU-to-CFM rule reliable?
It's a reasonable minimum baseline, but it assumes the hood actually delivers its rated CFM in your kitchen (it won't — see ductwork losses above) and that volume alone is sufficient for clean air (it isn't — velocity and capture efficiency matter more). Use the rule as a floor, not a ceiling.
Why do some hoods perform better at lower CFM ratings?
Because they're engineered to deliver their airflow more effectively. Higher intake velocity, better capture geometry, and anti-escape features mean more pollutants are actually captured per cubic foot of air moved. It's the difference between a targeted approach and brute force.
