Flow Hood CFM Calculator
Correct a balometer flow hood reading for its calibration factor.
Enter your values
Enter the flow hood reading in CFM.
Enter the correction factor (k) you are working with.
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.
- Corrected airflow
- 152.3 CFM
- Correction applied
- 5%
- Raw reading
- 145 CFM
Quick answer
Corrected CFM equals the flow hood's displayed reading multiplied by its calibration correction factor for that register type.
CFM_corrected = CFM_reading x K_factor
At a glance
| What it does | Correct a balometer flow hood reading for its calibration factor. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Flow hood reading, Correction factor (K) |
| Main output | Corrected airflow |
| Formula | CFM_corrected = CFM_reading x K_factor |
| Cost | Free — no sign-up, no download |
How to use the Flow Hood CFM Calculator
- 1Read the raw CFM shown on the flow hood display.
- 2Apply the manufacturer's correction factor for the specific diffuser or grille type (often 0.9-1.15).
- 3Use the corrected value for TAB (testing, adjusting, balancing) reports.
Inputs explained
- Flow hood reading(CFM)
- Enter the flow hood reading in CFM.
- Correction factor (K)
- Enter the correction factor (k) you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Flow hood reading145 CFM
- Correction factor (K)1.05
Results
- Corrected airflow152.3 CFM
- Correction applied5%
- Raw reading145 CFM
Frequently asked questions
Why is a correction needed?
Capture hoods disturb the natural flow pattern of some diffusers, causing a small but consistent reading error.
Where do I get K factors?
From the flow hood or diffuser manufacturer's published correction tables for each diffuser model.
What do I need to enter into the Flow Hood CFM Calculator?
Just 2 values: flow hood reading, correction factor (k). 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 Flow Hood CFM Calculator work out the answer?
Corrected CFM equals the flow hood's displayed reading multiplied by its calibration correction factor for that register type. It applies the formula CFM_corrected = CFM_reading x K_factor and shows the working so you can check each step by hand.
Is the 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.