30 vs 36 Inch Range Hood: Sizing Guide for Your Cooktop

Size your range hood to at least the width of your cooktop. A 30-inch range needs at least a 30-inch hood, and a 36-inch range needs at least a 36-inch hood. If you have the space, going one size up, such as a 36-inch hood over a 30-inch range, catches noticeably more smoke and grease, which is worth it for gas and heavy cooking.

At a glance

The basic rule: match or exceed the cooktop

Smoke, steam and grease rise in a plume that widens as it climbs. By the time it reaches a hood 24–36 inches above the burners, it is wider than the pot it came from. A hood that is exactly as wide as the cooktop leaves the outside edges of the plume on the front and side burners partly outside the canopy.

That leads to three rules manufacturers and installers use:

1. Never go narrower than the cooktop. A 30” hood over a 36” range leaves the outer burners uncovered, and more CFM does not fix it. Air pulled from the sides of a hood has to travel sideways to get there, and a rising plume does not do that.
2. Match the cooktop as the minimum. For electric or induction cooking of everyday meals, a matched width usually works.
3. Go 3 inches wider on each side for gas and heavy cooking. That turns a 30” range into a 36” hood and a 36” range into a 42” hood.

When a 36-inch hood over a 30-inch range makes sense

The upgrade pays off when:

• You cook on gas. Gas flames produce heat, moisture and combustion byproducts, and the hot air rises faster and spreads wider. Extra width catches more of it.
• You fry, sear, stir-fry or use a wok. High heat creates big plumes and more grease.
• You use the front burners a lot. Front burners are the hardest for any hood to cover.
• The hood sits near the top of its height range. A higher hood meets a wider plume.
• Your kitchen is open-plan. Smoke that escapes spreads further, and cross drafts from windows, doors and walkways push the plume sideways.

It may not be worth it when you cook mostly on electric or induction with lids on, when the hood is mounted at the low end of its height range, or when the layout does not allow it.

Cabinet and wall constraints

Before you buy a 36” hood for a 30” range, check what the space allows.

Under-cabinet hoods

An under-cabinet hood mounts beneath the cabinet above the range, which is typically the same width as the range opening, 30” in most kitchens. A 36” under-cabinet hood does not fit a 30” cabinet opening without changes. Your options:

• Replace the 30” upper cabinet with a 36” one and trim or replace the cabinets on each side.
• Switch to a wall-mount chimney hood, which only needs clear wall space. See under-cabinet vs wall-mount range hood.
• Stay at 30” and make up for it with the right CFM, a lower mounting height (within the manual’s range) and the back burners.

Also check the side clearance. Tall cabinets, a fridge panel or a side wall next to the range may block a wider hood.

Wall-mount chimney hoods

A wall-mount hood needs clear wall above the range. A 36” hood over a 30” range extends 3” past the range on each side. Measure the wall space, look for windows, outlets and cabinets that the hood would hit, and confirm there is room for the chimney cover up to the ceiling.

Over-the-range microwave replacement

If you are replacing a 30” over-the-range microwave, the opening is almost always 30” wide between cabinets. A 30” under-cabinet hood is the easy swap. Our guide to range hood vs over-the-range microwave covers that change.

Island hood sizing

Island hoods have no wall behind them, so drafts can push smoke out from every side. That is why the rule is stricter: overhang the cooktop by about 3” on each side, 6” total.

Island hoods also need more airflow. A common rule is about 150 CFM per linear foot of cooktop width, compared with about 100 CFM per foot for wall hoods. See island vs wall-mount range hood for more on island ventilation.

Width and CFM together

Width and CFM work together. A wider hood covers more area and usually needs more airflow to keep up at the edges. Use all of these rules and pick the highest result:

• Gas: about 100 CFM per 10,000 BTU of total burner output. A 30” gas range with four burners totalling 50,000 BTU needs about 500 CFM.
• Electric or induction: about 10 CFM per inch of cooktop width. A 30” range needs about 300 CFM, a 36” range about 360 CFM.
• Hood placement: about 100 CFM per foot of cooktop width for wall hoods (a 36” cooktop is about 300 CFM) and about 150 CFM per foot for island hoods (a 36” cooktop is about 450 CFM).
• Room size: kitchen volume in cubic feet × 15 air changes per hour ÷ 60.

Our CFM calculator runs all of these at once and also suggests a duct size. For a closer look at the airflow trade-offs, see 300 vs 400 vs 600 CFM range hoods.

Remember that the ductwork has to keep up. A 6” round duct is typical up to about 400 CFM; 7–8” for around 600 CFM. And under IRC 2021 Section M1503.6, a system able to exhaust more than 400 CFM needs makeup air. Check with your local building department.

Cost, noise and installation

Cost. A 36” hood usually costs somewhat more than the 30” version of the same design, and the gap is small compared with the cost of changing cabinets. If a 36” hood means replacing an upper cabinet, the cabinet work can cost more than the hood.

Noise. A 36” hood often has a larger motor or a second blower, so it can be louder at high speed. Compare sone ratings at low and high speeds. Because a wider hood captures better, you can often run it one speed lower than a narrower hood for the same result, which is quieter in practice.

Installation. Width alone does not change how the hood is wired or ducted. Wider hoods are heavier, so make sure the mounting surface has solid backing, and plan on two people to lift it.

Which should you choose?

Choose a 30-inch hood if:

• You have a 30” range with a 30” cabinet opening and do not want to change the cabinets.
• You cook mostly on electric or induction, with moderate heat.
• You are swapping out an over-the-range microwave.
• Budget is tight and the cooktop is 30” or narrower.

Choose a 36-inch hood if:

• You have a 36” range or cooktop (a 36” hood is the minimum).
• You have a 30” gas range and wall space for a wider wall-mount hood.
• You fry, sear or wok-cook often.
• The hood is over a 30” island cooktop.
• Your kitchen is open to living areas and you want to keep smells in the kitchen.

Go wider than 36 inches if: you have a 36” gas range (42”), a 36” island cooktop (42”) or a 48” range (48–54”).

What to look for when buying

• Hood width equal to or wider than your cooktop, measured in inches, not from the product name
• 3” extra per side for gas, heavy cooking or islands
• Cabinet opening and side clearances measured before you order
• Wall space and ceiling height checked for wall-mount and chimney hoods
• CFM from the CFM calculator, using the highest result
• Duct size that matches the hood collar, never smaller
• Sone rating at low and high speed, ideally HVI-certified
• Mounting height range in the manual that suits your cooktop
• Makeup air plan if the hood can exhaust more than 400 CFM
• Solid wall backing for the extra weight of a wider hood

The bottom line

Never go narrower than your cooktop. A 30” hood over a 30” range is the standard, workable setup for everyday electric cooking. If you cook on gas or cook hot and often, and the space allows it, a 36” hood over a 30” range is one of the simplest ways to make any hood work better.