Fan Temperature Correction Calculator
Correct fan pressure and BHP rating for high or low air temperature.
Enter your values
Enter the rated static pressure (at 70f) in in wc.
Enter the rated brake hp (at 70f) in hp.
Enter the actual air temperature in F.
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 static pressure
- 1.743 in wc
- Corrected brake horsepower
- 3.487 hp
- Correction factor
- 0.697
Quick answer
Fan pressure and power scale directly with the ratio of standard absolute temperature to actual absolute temperature.
Correction factor = (460+70) / (460+T_actual)
At a glance
| What it does | Correct fan pressure and BHP rating for high or low air temperature. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Rated static pressure (at 70F), Rated brake HP (at 70F), Actual air temperature |
| Main output | Corrected static pressure |
| Formula | Correction factor = (460+70) / (460+T_actual) |
| Cost | Free — no sign-up, no download |
How to use the Fan Temperature Correction Calculator
- 1Enter the fan's rated static pressure and horsepower, typically given at standard 70F air.
- 2Enter the actual continuous operating air temperature.
- 3Read the corrected pressure and power the fan will actually produce and draw at that temperature.
Inputs explained
- Rated static pressure (at 70F)(in wc)
- Enter the rated static pressure (at 70f) in in wc.
- Rated brake HP (at 70F)(hp)
- Enter the rated brake hp (at 70f) in hp.
- Actual air temperature(F)
- Enter the actual air temperature in F.
Worked example
Using the values the calculator loads with:
Inputs
- Rated static pressure (at 70F)2.5 in wc
- Rated brake HP (at 70F)5 hp
- Actual air temperature300 F
Results
- Corrected static pressure1.743 in wc
- Corrected brake horsepower3.487 hp
- Correction factor0.697
Frequently asked questions
Why does hot air reduce pressure?
Hot air is less dense, so the same fan wheel speed moves the same volume but less mass, producing less pressure and requiring less power.
Is this the same for cooling air below 70F?
Yes, the same ratio applies — colder, denser air increases both pressure and power above the 70F rating.
What do I need to enter into the Fan Temperature Correction Calculator?
Just 3 values: rated static pressure (at 70f), rated brake hp (at 70f), actual air temperature. 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 Temperature Correction Calculator work out the answer?
Fan pressure and power scale directly with the ratio of standard absolute temperature to actual absolute temperature. It applies the formula Correction factor = (460+70) / (460+T_actual) and shows the working so you can check each step by hand.
Is the Fan Temperature Correction 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.