Static Pressure Calculator
Total external static pressure health check.
Enter your values
Enter the supply static in in w.c..
Enter the return static in in w.c..
Enter the blower rated static in in w.c..
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 external static
- 0.78 in w.c.
- Percent of blower rating
- 156%
- Dominant restriction
- supply side
- In pascals
- 194
- Verdict
- Over rating — airflow and capacity are suffering
Quick answer
Total external static pressure is the supply reading plus the absolute value of the return reading, and should stay at or under the blower's rating, usually 0.5 in w.c.
TESP = supply static + |return static|
At a glance
| What it does | Total external static pressure health check. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Supply static, Return static, Blower rated static |
| Main output | Total external static |
| Formula | TESP = supply static + |return static| |
| Cost | Free — no sign-up, no download |
How to use the Static Pressure Calculator
- 1Drill test ports upstream and downstream of the air handler.
- 2Record the supply and return readings with a manometer.
- 3Enter the blower's rated static from the data plate.
Inputs explained
- Supply static(in w.c.)
- Enter the supply static in in w.c..
- Return static(in w.c.)
- Enter the return static in in w.c..
- Blower rated static(in w.c.)
- Enter the blower rated static in in w.c..
Worked example
Using the values the calculator loads with:
Inputs
- Supply static0.42 in w.c.
- Return static0.36 in w.c.
- Blower rated static0.5 in w.c.
Results
- Total external static0.78 in w.c.
- Percent of blower rating156%
- Dominant restrictionsupply side
- In pascals194
- VerdictOver rating — airflow and capacity are suffering
Frequently asked questions
What is a good static pressure?
0.5 in w.c. or less total on most residential equipment; many real systems measure 0.8 or worse.
What causes high static?
Undersized returns, dirty filters, crushed flex duct and restrictive coils are the usual culprits.
What do I need to enter into the Static Pressure Calculator?
Just 3 values: supply static, return static, blower rated static. 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 Static Pressure Calculator work out the answer?
Total external static pressure is the supply reading plus the absolute value of the return reading, and should stay at or under the blower's rating, usually 0.5 in w.c. It applies the formula TESP = supply static + |return static| and shows the working so you can check each step by hand.
Is the 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.