Fan Total Efficiency Calculator
Total (mechanical) efficiency from CFM, total pressure and power.
Enter your values
Enter the airflow in CFM.
Enter the total pressure in in wc.
Enter the brake horsepower in hp.
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.
- Total efficiency
- 58.1%
- Air power (total)
- 3.78 hp
- Loss to shaft power
- 2.72 hp
Quick answer
Total efficiency equals CFM times total pressure divided by 6356 times brake horsepower.
eff_total = CFM x TP / (6356 x BHP)
At a glance
| What it does | Total (mechanical) efficiency from CFM, total pressure and power. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Airflow, Total pressure, Brake horsepower |
| Main output | Total efficiency |
| Formula | eff_total = CFM x TP / (6356 x BHP) |
| Cost | Free — no sign-up, no download |
How to use the Fan Total Efficiency Calculator
- 1Enter CFM, total pressure and brake horsepower from a field test or manufacturer curve.
- 2Read the total efficiency, the true measure of aerodynamic performance.
- 3Compare against catalogue data to confirm the fan is running near its best efficiency point.
Inputs explained
- Airflow(CFM)
- Enter the airflow in CFM.
- Total pressure(in wc)
- Enter the total pressure in in wc.
- Brake horsepower(hp)
- Enter the brake horsepower in hp.
Worked example
Using the values the calculator loads with:
Inputs
- Airflow8000 CFM
- Total pressure3.0 in wc
- Brake horsepower6.5 hp
Results
- Total efficiency58.1%
- Air power (total)3.78 hp
- Loss to shaft power2.72 hp
Frequently asked questions
Why use total instead of static pressure?
Total pressure accounts for velocity energy, giving a true measure of useful work done on the air.
Typical peak values?
Well-designed airfoil centrifugal fans can exceed 85% total efficiency at their best point.
What do I need to enter into the Fan Total Efficiency Calculator?
Just 3 values: airflow, total pressure, brake horsepower. 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 Fan Total Efficiency Calculator work out the answer?
Total efficiency equals CFM times total pressure divided by 6356 times brake horsepower. It applies the formula eff_total = CFM x TP / (6356 x BHP) and shows the working so you can check each step by hand.
Is the Fan Total Efficiency 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.