Laminar Flow Hood CFM Calculator
Airflow for a clean bench or flow hood.
Enter your values
Enter the filter width in in.
Enter the filter height in in.
Enter the face velocity in FPM.
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.
- Required blower
- 600 CFM
- At 1.0 in wc static
- 690 CFM rating advised
- Filter face area
- 6 sq ft
- Air changes in a 4x2x2 ft work zone
- 2250
Quick answer
Laminar flow hoods run at about 100 feet per minute across the filter face, so CFM equals filter area times 100.
CFM = w x h / 144 x 100
At a glance
| What it does | Airflow for a clean bench or flow hood. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Filter width, Filter height, Face velocity |
| Main output | Required blower |
| Formula | CFM = w x h / 144 x 100 |
| Cost | Free — no sign-up, no download |
How to use the Laminar Flow Hood CFM Calculator
- 1Measure the HEPA filter face you plan to use.
- 2Keep face velocity at 90-110 FPM for sterile work.
- 3Choose a blower rated for that CFM at 1.0-1.5 in wc, since a loaded HEPA is restrictive.
Inputs explained
- Filter width(in)
- Enter the filter width in in.
- Filter height(in)
- Enter the filter height in in.
- Face velocity(FPM)
- Enter the face velocity in FPM.
Worked example
Using the values the calculator loads with:
Inputs
- Filter width36 in
- Filter height24 in
- Face velocity100 FPM
Results
- Required blower600 CFM
- At 1.0 in wc static690 CFM rating advised
- Filter face area6 sq ft
- Air changes in a 4x2x2 ft work zone2250
Frequently asked questions
Why 100 FPM?
It is fast enough to sweep contaminants away but slow enough to stay laminar and not disturb plates.
Horizontal or vertical?
Horizontal suits mycology and plant culture; vertical is better when you need to protect the operator too.
What do I need to enter into the Laminar Flow Hood CFM Calculator?
Just 3 values: filter width, filter height, face velocity. 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 Laminar Flow Hood CFM Calculator work out the answer?
Laminar flow hoods run at about 100 feet per minute across the filter face, so CFM equals filter area times 100. It applies the formula CFM = w x h / 144 x 100 and shows the working so you can check each step by hand.
Is the Laminar Flow Hood 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.