Range Hood Size and CFM Calculator
Choose wall or island, the width of your cooktop or range, and your fuel to see the minimum hood width and the CFM figures from the makers' own guidance. Each number names its source: Wolf, Vent-A-Hood, or Zephyr. The installation guide for the hood you choose and your local building department have the final word.
Size your hood
Hood width
At least 36 inches
Wolf says a wall hood should be at least as wide as the cooking surface.
Over a 36-inch cooking surface, that means a 36-inch hood at minimum, and 42 inches if you want the 3-inch overhang Vent-A-Hood recommends on each side.
Blower size
800 CFM
Wolf's ventilation guide suggests 800 CFM for its 36-inch gas range.
Wolf adds that long duct runs and ranges with a charbroiler or griddle may need more.
Enter your burners' total BTUs to add Zephyr's rule.
Make-up air
Above 400 CFM
Zephyr notes that many local codes limit hood airflow to 400 CFM if no make-up air kit is used.
Your local building department decides what applies to your home, so ask before you settle on a blower, and have a licensed HVAC contractor design any make-up air system.
Hood width by cooking surface
| Cooking surface | Wall hood | Wall, 3-inch overhang | Island hood |
|---|---|---|---|
| 30-inch | 30 in | 36 in | 36 in |
| 36-inch | 36 in | 42 in | 42 in |
| 48-inch | 48 in | 54 in | 54 in |
| 60-inch | 60 in | 66 in | 66 in |
Minimum widths, plus the width with Vent-A-Hood's recommended 3-inch overhang on each side. Sources: Wolf Ventilation Guide (rev. 1/2023) and Vent-A-Hood's Magic Lung owner's guide.
CFM figures by cooking surface
| Cooking surface | Wolf gas range | Wolf induction range | Zephyr electric rule |
|---|---|---|---|
| 30-inch | 500 CFM | 300 CFM | 375 CFM |
| 36-inch | 800 CFM | 300 CFM | 450 CFM |
| 48-inch | 1,100 CFM | Not listed | 600 CFM |
| 60-inch | 1,500 CFM | Not listed | 750 CFM |
Wolf's figures are for its own ranges. Sources: Wolf Ventilation Guide (rev. 1/2023) and Zephyr's product education page.
How the numbers work
A hood can only exhaust the smoke it catches. Steam and grease rise and spread, so the canopy has to be big enough and low enough to collect them.
Width
- Wolf says a wall hood should be at least as wide as the cooking surface, and that a wider hood increases the capture area where space allows.
- Zephyr says the hood width should equal the width of the cooktop or range.
- Vent-A-Hood recommends overlapping the cooking equipment by at least 3 inches on each side whenever possible, and calls it mandatory for islands.
- Wolf says island and peninsula installations need more capture area, and that an island hood should exceed the cooking surface by at least 3 inches on each side.
Heavy cooking raises the bar. Wolf says high heat or aromatic foods may call for more CFM and a hood that exceeds the cooking surface by 3 inches on each side, even on a wall.
CFM
CFM, cubic feet per minute, is how much air the blower moves.
- Zephyr's rule for gas is to divide the total BTUs by 100. For electric, Zephyr multiplies the linear feet of cooking surface by 150.
- Wolf's ventilation guide suggests 500 CFM for its 30-inch gas range, 800 for 36-inch, 1,100 for 48-inch, and 1,500 for 60-inch, and 300 for its 30- and 36-inch induction ranges. Wolf adds that long duct runs and ranges with a charbroiler or griddle may need more.
- Vent-A-Hood's owner's guide matches a 300 CFM blower to standard 4-burner cooking, 600 CFM to standard and pro-style ranges, and 900 or 1,200 CFM to larger pro-style ranges.
More CFM has trade-offs. A bigger blower needs duct sized to carry the air, and it can trigger make-up air requirements, covered below. Size it to the cooking, then stop.
Make-up air
A strong hood pulls air out of the house, and that air has to come back from somewhere. Wolf says make-up air may be required and tells you to consult a qualified HVAC professional. Zephyr notes that many local codes limit hood airflow to 400 CFM if no make-up air kit is used. Your local building department decides what applies to your home, so ask before you settle on a blower, and have a licensed HVAC contractor design any make-up air system.
For hood types, blower positions, duct runs, and noise, read our guide to choosing a range hood.
Before you order
- Vent-A-Hood says the hood should project out to the front edge of the front burners.
- Follow the hood's own installation guide. Wolf recommends 30 to 36 inches from the countertop to the bottom of its pro hoods.
- Zephyr says that for every 3 inches beyond the recommended mounting height, you should increase the hood width by 3 inches on each side.
- Use rigid, smooth-walled metal duct. Wolf says its hoods work most efficiently with a run of 50 feet or less.
- If you're also planning a pro-style range, our checklist for a pro-style gas range covers the range side of the same wall.
- For what happens after the order, see our delivery and installation page.
The hood makers on our line card include Wolf, Vent-A-Hood, Zephyr, BEST, Elica, Trade-Wind, and Sapphire. Ask us for current spec sheets if any of them is on your list. Our range hoods and ventilation page shows the full category.