The Right CFM Depends on Your Stove Size and Cooking Style

CFM stands for cubic feet per minute — the volume of air your range hood pulls out of the kitchen each minute. A hood that is too weak will leave grease and odors in your kitchen; one that is oversized will waste energy and create unnecessary noise. The number you need depends on your cooktop width, how often you cook, and whether you cook foods that produce heavy smoke or steam.

Most home cooks need between 100 and 400 CFM. A 30-inch electric cooktop in a kitchen where you bake and simmer most days typically needs 200 to 300 CFM. A 36-inch gas range where you sear meat and stir-fry regularly needs 300 to 400 CFM or higher. If your kitchen is very small or you rarely cook, 100 to 150 CFM may be enough. The key is matching the hood's power to what actually happens at your stove.

Key Takeaways

  • A general rule is 100 CFM per 10 inches of cooktop width, so a 30-inch stove needs roughly 300 CFM and a 36-inch stove needs roughly 360 CFM.
  • Gas cooktops produce more heat and smoke than electric ones, so a gas range of the same width typically needs 50 to 100 CFM more than an electric model.
  • If your kitchen is open to other rooms or you cook bold foods like fish or curry regularly, add 50 to 100 CFM to your base number.
  • The CFM rating on the hood's box is measured in ideal conditions; real-world performance drops when the hood is installed, so choose a model rated slightly higher than your calculated need.

Calculate CFM Based on Cooktop Width

The simplest starting point is cooktop width. Multiply your stove's width in inches by 10, and that gives you a baseline CFM target. A 30-inch cooktop suggests 300 CFM; a 36-inch cooktop suggests 360 CFM; a 24-inch cooktop suggests 240 CFM.

This rule works because a wider cooktop produces more steam and smoke across a larger area, and the hood needs proportionally more airflow to capture it all. A 30-inch electric range where you mostly boil pasta and roast vegetables can often work with 250 to 280 CFM. The same 30-inch range used for high-heat searing or wok cooking should have 320 to 350 CFM. Write down your cooktop width and add or subtract based on how you actually cook.

Gas Ranges Need More CFM Than Electric

Gas cooktops burn fuel directly under the pan, which produces more heat, more moisture, and more combustion byproducts than electric coils or a smooth glass top. For the same cooktop width, a gas range typically needs 50 to 100 CFM more than an electric model.

A 30-inch electric cooktop might work well at 280 CFM, but a 30-inch gas range should have 330 to 380 CFM. A 36-inch gas range often needs 400 to 500 CFM, especially if you use the burners at high heat regularly. If you are replacing an old hood with a new one and you have a gas stove, do not assume the old hood's CFM rating is correct — many older hoods were undersized, and you may notice a real difference with a more powerful model.

Adjust for Kitchen Layout and Cooking Habits

An open kitchen where the cooking area connects to a dining room or living room loses more air to those spaces, so the hood has to work harder to pull smoke and steam away from the stove. If your kitchen is open on one or more sides, add 50 to 100 CFM to your baseline number. A closed kitchen with a door can use a lower CFM because the air has nowhere else to go.

Your cooking style also matters. If you regularly cook foods that produce heavy smoke or steam — fish, curry, stir-fries, searing meat, boiling pasta — choose a hood at the higher end of the range for your cooktop size. If you mostly bake, simmer soups, or reheat leftovers, you can stay at the lower end. Some cooks find that a hood rated 50 CFM higher than the calculated minimum gives them more flexibility without being uncomfortably loud.

Account for Real-World Performance Loss

The CFM number printed on a range hood's box is measured in a laboratory with the hood running in ideal conditions — no ductwork, no bends, no obstacles. Once the hood is installed in your home, the actual airflow drops. A long duct run, tight elbows, or a damper that does not open fully can reduce real performance by 10 to 30 percent.

If your ductwork runs more than 10 feet from the hood to the outside wall, or if the duct has more than two 90-degree bends, choose a hood rated 50 to 100 CFM higher than your calculated need. If the duct is short and straight, you can stay closer to your target number. Ask the installer or the hood manufacturer how much performance loss to expect with your specific ductwork setup.

Understand the Difference Between Ducted and Ductless Hoods

A ducted hood pulls air out of the kitchen and vents it to the outside through a duct. These hoods can use the full CFM rating because the air actually leaves the house. A ductless hood (or recirculating hood) pulls air through a filter and pushes it back into the kitchen. Ductless hoods are easier to install but less effective at removing heat and moisture, and they require frequent filter changes.

If you are choosing between a ducted and ductless hood, a ducted model at 250 to 300 CFM will outperform a ductless model at 400 CFM because the ducted hood actually removes the air instead of recirculating it. Most building codes and appliance manufacturers recommend ducted hoods for gas cooktops. If you must use a ductless hood, choose one rated at least 50 CFM higher than you would for a ducted model, and plan to replace the filters every 3 to 6 months.

Noise Level and CFM Trade-Offs

A more powerful hood moves more air, but it also makes more noise. CFM and noise level are linked — a 400 CFM hood will be noticeably louder than a 250 CFM hood, often by 5 to 10 decibels. Noise is measured in sones; most people find hoods quieter than 1 sone acceptable for daily use, and hoods above 2 sones annoying during conversation.

Check the hood's noise rating (listed in sones) before you buy, not just the CFM. Some manufacturers make hoods with variable speed controls, which let you run at lower CFM and lower noise for everyday cooking, then ramp up for heavy-duty jobs. If noise is a concern in your kitchen, a 300 CFM hood with a low-noise motor may feel better than a 400 CFM hood that sounds like a jet engine.

Frequently Asked Questions

Is 200 CFM enough for a 30-inch electric stove?

For light cooking — baking, simmering, reheating — 200 CFM can work, but it is below the standard guideline of 100 CFM per 10 inches of width. If you cook bold foods or use high heat regularly, you will notice odors lingering. 250 to 280 CFM is a safer choice for a 30-inch electric range.

How much CFM do I need for a gas range?

A 30-inch gas range typically needs 330 to 380 CFM; a 36-inch gas range needs 400 to 500 CFM. Gas produces more heat and moisture than electric, so do not use the same CFM number you would for an electric cooktop of the same width. If your kitchen is open or you cook high-heat foods often, choose the higher end of that range.

Can I use a ductless hood instead of a ducted one?

Ductless hoods are easier to install but less effective at removing heat and odors because they recirculate air instead of venting it outside. If you must use ductless, choose a model rated 50 CFM higher than you would for a ducted hood, and replace the filters every 3 to 6 months. Ducted hoods are recommended for gas cooktops.

Does a longer duct reduce the hood's CFM?

Yes. A duct longer than 10 feet or with more than two 90-degree bends can reduce real-world airflow by 10 to 30 percent. If your ductwork is long or has tight turns, choose a hood rated 50 to 100 CFM higher than your calculated need to account for this loss.

What if my kitchen is very small?

A small, closed kitchen with a 24-inch electric cooktop may only need 150 to 200 CFM because there is less volume to ventilate and nowhere for air to escape. However, if you cook frequently or use high heat, do not go below 150 CFM — undersized hoods leave grease and odors in the space.