Restaurant Exhaust CFM Calculator
Commercial kitchen hood exhaust airflow.
Enter your values
Enter the hood length in ft.
Choose one of: Wall-mounted canopy, Island canopy, Proximity / backshelf.
Choose one of: Light (ovens), Medium (fryers, ranges), Heavy (charbroiler), Extra heavy (solid fuel).
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Exhaust airflow
- 3,000 CFM
- Rate
- 300 CFM per linear foot
- Makeup air (80%)
- 2,400 CFM
- Duct area at 1800 FPM
- 1.67 sq ft
- Fan static allowance
- 1.0 - 1.5 in wc typical
Quick answer
Commercial hood exhaust is sized in CFM per linear foot of hood, rising with appliance duty from light to extra heavy.
CFM = hood length x CFM per linear foot
At a glance
| What it does | Commercial kitchen hood exhaust airflow. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Hood length, Hood type, Appliance duty |
| Main output | Exhaust airflow |
| Formula | CFM = hood length x CFM per linear foot |
| Cost | Free — no sign-up, no download |
How to use the Restaurant Exhaust CFM Calculator
- 1Measure the hood length and identify the heaviest appliance under it.
- 2Choose the hood style — island hoods need substantially more air.
- 3Provide 80-90% of the exhaust as tempered makeup air.
Inputs explained
- Hood length(ft)
- Enter the hood length in ft.
- Hood type
- Choose one of: Wall-mounted canopy, Island canopy, Proximity / backshelf.
- Appliance duty
- Choose one of: Light (ovens), Medium (fryers, ranges), Heavy (charbroiler), Extra heavy (solid fuel).
Worked example
Using the values the calculator loads with:
Inputs
- Hood length10 ft
- Hood typeWall-mounted canopy
- Appliance dutyMedium (fryers, ranges)
Results
- Exhaust airflow3,000 CFM
- Rate300 CFM per linear foot
- Makeup air (80%)2,400 CFM
- Duct area at 1800 FPM1.67 sq ft
- Fan static allowance1.0 - 1.5 in wc typical
Frequently asked questions
Why is island so much higher?
There are no side walls to contain the plume, so cross drafts pull effluent out.
Can I undersize to save energy?
No — undersized hoods spill grease-laden vapour into the kitchen and fail inspection.
What do I need to enter into the Restaurant Exhaust CFM Calculator?
Just 3 values: hood length, hood type, appliance duty. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Restaurant Exhaust CFM Calculator work out the answer?
Commercial hood exhaust is sized in CFM per linear foot of hood, rising with appliance duty from light to extra heavy. It applies the formula CFM = hood length x CFM per linear foot and shows the working so you can check each step by hand.
Is the Restaurant Exhaust CFM Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.