Commercial Kitchen Exhaust Hood Calculator
Estimate preliminary commercial kitchen hood exhaust airflow from hood dimensions and cooking duty, with results in CFM and m³/h.
Hood area
24 ft²
Estimated exhaust
1,680 CFM
Metric airflow
2,854 m³/h
Preliminary Greenheck guidance only when a different rate is not specified by code or the listed hood manufacturer.
Turn the calculation into a complete design workflow
Use the free result as a quick engineering check, then continue into MEPFlow for connected system design, sizing and project calculations.
How the Commercial Kitchen Exhaust Hood Calculator Works
This estimator uses published Greenheck guidance for commercial kitchen applications when an exhaust rate is not otherwise specified by code or the hood listing. The guidance uses 50 CFM/ft² for light-duty cooking, 70 CFM/ft² for medium-duty cooking and 100 CFM/ft² for heavy-duty cooking.
Enter the physical hood length and depth rather than appliance footprint. The calculator multiplies hood plan area by the selected duty rate, then converts the result to metric airflow for quick equipment comparison.
A listed Type I or Type II hood can have manufacturer-specific exhaust requirements that differ from a simple area method. Treat this result as a preliminary design check and verify the final airflow against the hood listing, local code and authority having jurisdiction.
Calculation basis
Exhaust CFM = Hood Area (ft²) × Exhaust Rate (CFM/ft²)
When to Use This Calculator
- Early kitchen ventilation layouts
- Preliminary exhaust fan selection
- Makeup-air coordination
- Quick hood airflow checks
Engineering Checks Before Final Design
- Do not override a listed hood airflow requirement.
- Local code may require a different minimum rate.
- Grease duct and fire-suppression design are outside this calculator.
Frequently Asked Questions
What is light-duty cooking?
Greenheck examples include ovens, ranges and kettles. Confirm the actual appliance duty classification for the project before final design.
Does hood depth affect exhaust CFM?
Yes in this area-based method. A deeper hood has more plan area, so the calculated exhaust airflow increases.
Should I size makeup air to the same CFM?
Not automatically. Building pressurization, transfer air and hood strategy determine the replacement-air fraction. Use the MEPFlow makeup-air calculator as the next check.
Is this a code-compliance calculator?
No. It is a preliminary engineering estimator based on published manufacturer guidance and must be checked against the adopted code and listed equipment.
Engineering References
MEPFlow uses public engineering references to document the calculation basis. Always verify the final design against the standard, code edition and manufacturer data applicable to your project.