Total vs Static Pressure Calculator
Split total pressure into static and velocity components.
Enter your values
Enter the airflow in CFM.
Enter the duct area in sq ft.
Enter the static pressure in in wc.
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.
- Duct velocity
- 1,500 FPM
- Velocity pressure
- 0.1403 in wc
- Total pressure
- 2.14 in wc
- Static regain factor
- 0.934
Quick answer
Total pressure equals static pressure plus velocity pressure, where velocity pressure is derived from duct velocity.
TP = SP + VP; VP = (V/4005)^2
At a glance
| What it does | Split total pressure into static and velocity components. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Airflow, Duct area, Static pressure |
| Main output | Duct velocity |
| Formula | TP = SP + VP; VP = (V/4005)^2 |
| Cost | Free — no sign-up, no download |
How to use the Total vs Static Pressure Calculator
- 1Enter airflow, duct cross-section area and the measured static pressure.
- 2The tool converts velocity into velocity pressure and adds it to static pressure.
- 3Use total pressure, not static alone, for accurate fan brake horsepower calculations.
Inputs explained
- Airflow(CFM)
- Enter the airflow in CFM.
- Duct area(sq ft)
- Enter the duct area in sq ft.
- Static pressure(in wc)
- Enter the static pressure in in wc.
Worked example
Using the values the calculator loads with:
Inputs
- Airflow6000 CFM
- Duct area4 sq ft
- Static pressure2.0 in wc
Results
- Duct velocity1,500 FPM
- Velocity pressure0.1403 in wc
- Total pressure2.14 in wc
- Static regain factor0.934
Frequently asked questions
Why does velocity pressure matter?
It represents the kinetic energy of the moving air and is always part of the total energy the fan must supply.
What is 4005?
It is the standard constant relating FPM to velocity pressure in inches of water at standard air density.
What do I need to enter into the Total vs Static Pressure Calculator?
Just 3 values: airflow, duct area, static pressure. 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 Total vs Static Pressure Calculator work out the answer?
Total pressure equals static pressure plus velocity pressure, where velocity pressure is derived from duct velocity. It applies the formula TP = SP + VP; VP = (V/4005)^2 and shows the working so you can check each step by hand.
Is the Total vs Static Pressure 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.