Pitot Tube Traverse Calculator
Average duct velocity and CFM from multiple pitot readings.
Enter your values
Enter the velocity pressures (comma-separated) in in wc.
Enter the duct area in sq ft.
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.
- Average velocity
- 1,853 FPM
- Airflow
- 5,559 CFM
- Number of points
- 6
- Average VP
- 0.215 in wc
Quick answer
Traverse velocity is found by averaging the square roots of each velocity pressure reading, then converting to velocity and multiplying by area.
V = 4005 x average(sqrt(VP_i)); CFM = V x Area
At a glance
| What it does | Average duct velocity and CFM from multiple pitot readings. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Velocity pressures (comma-separated), Duct area |
| Main output | Average velocity |
| Formula | V = 4005 x average(sqrt(VP_i)); CFM = V x Area |
| Cost | Free — no sign-up, no download |
How to use the Pitot Tube Traverse Calculator
- 1Take pitot-tube velocity pressure readings at equal-area points across the duct (log-Tchebycheff or equal-area grid).
- 2Enter all readings comma-separated and the duct area.
- 3Read the average velocity and resulting CFM.
Inputs explained
- Velocity pressures (comma-separated)(in wc)
- Enter the velocity pressures (comma-separated) in in wc.
- Duct area(sq ft)
- Enter the duct area in sq ft.
Worked example
Using the values the calculator loads with:
Inputs
- Velocity pressures (comma-separated)0.18, 0.22, 0.26, 0.24, 0.20, 0.19 in wc
- Duct area3.0 sq ft
Results
- Average velocity1,853 FPM
- Airflow5,559 CFM
- Number of points6
- Average VP0.215 in wc
Frequently asked questions
Why average square roots and not VP directly?
Velocity is proportional to the square root of VP, so averaging velocities (not pressures) gives the correct mean flow.
How many points are needed?
Typically 16-20 points for round ducts over 12 inches, fewer for smaller ducts.
What do I need to enter into the Pitot Tube Traverse Calculator?
Just 2 values: velocity pressures (comma-separated), duct area. 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 Pitot Tube Traverse Calculator work out the answer?
Traverse velocity is found by averaging the square roots of each velocity pressure reading, then converting to velocity and multiplying by area. It applies the formula V = 4005 x average(sqrt(VP_i)); CFM = V x Area and shows the working so you can check each step by hand.
Is the Pitot Tube Traverse 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.