Exhaust Fan Size Calculator: What Size Exhaust Fan Do I Need?

Calculate the proper exhaust fan size for your room by entering the details below. The calculator will determine the minimum CFM (Cubic Feet per Minute) required for proper ventilation.

Room Length (feet):

Room Width (feet):

Room Height (feet):

Room Fixtures (select all that apply):

Kitchen Laundry Garage Workshop

List of the Best Exhaust Fan:

#	Product	Link
1	Comfort Zone Window Fan for Bedroom, 9 inch 3 Speed Dual Fans with Auto-Locking Expanders, Window Exhaust Fan, Removeable Bug Screen, White	View on Amazon
2	Maxx Air HVHF 12COMBO Heavy Duty Portable Exhaust Fan - 2000 CFM, 12 Inch, 2 Speed Extractor Fan with 20 ft Hose - Ideal Exhaust Fan for Efficient Ventilation	View on Amazon
3	Utility Blower,8 Inch Exhaust Fan,2500R/MIN High Velocity Portable Ventilator,Air Extractor Fan with 16 Ft / 5m Duct Hose for Paint Booth,Industrial Basement and More	View on Amazon
4	Air King AS54 Advantage Bath 50-CFM at 3.0-Sones, White Finish Exhaust Fans, Medium	View on Amazon
5	Vornado TRANSOM Window Fan with 4 Speeds, Remote Control, Reversible Exhaust Mode, Weather Resistant Case, Black, Whole Room	View on Amazon

Complete Guide to Exhaust Ventilation and Fan Sizing

Understanding Exhaust Ventilation Requirements

Proper exhaust ventilation is critical for controlling humidity, odors, and contaminants in your space. The correct fan size ensures that air is effectively exchanged, removing unwanted pollutants.

CFM Calculation Guide

Exhaust fan size (CFM) is determined by the room's volume, fixtures, and the purpose of the room. Larger rooms with more moisture or pollutant-generating activities require larger fans.

Basic Method for CFM Calculation

Calculate the volume of the room (length × width × height)
For general rooms: multiply the volume by 0.13-0.15 CFM per cubic foot
For kitchens, laundries, workshops: higher CFM may be needed due to higher moisture or fumes