Fan Static Pressure Estimator
Estimate the total external static pressure a fan must overcome by adding duct friction, a fittings allowance and filter, coil, grille and other component pressure drops. Shows a component breakdown, a design margin and the fan air and shaft power.
Input
Used for every pressure entered and shown below.
Ductwork
Pressure per 100 ft (or per metre when length is in metres). Typical design: 0.08–0.10 in.wg/100 ft, or ~1 Pa/m.
Component Pressure Drops
Design Allowances
Total (static or overall) efficiency at the duty point. Leave blank to skip power.
Output
| Component | Pressure |
|---|---|
| No data yet | |
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/fan-static-pressure-estimator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"airflow": "2000",
"flowUnit": "cfm",
"pressureUnit": "inwg",
"ductLength": "100",
"lengthUnit": "ft",
"frictionRate": "0.08",
"fittingsAllowance": "50",
"filter": "0.5",
"coil": "0.4",
"grille": "0.1",
"other": "0.1",
"margin": "10",
"fanEfficiency": "60"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `fan-static-pressure-estimator` tool (Fan Static Pressure Estimator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
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src="https://iotools.cloud/embed/fan-static-pressure-estimator/"
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allow="clipboard-write"
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<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
Add up the pressure a fan has to overcome: straight-duct friction, a fittings allowance, filter, coil, grille or diffuser and any other component. You get a component breakdown, a design pressure with margin in both in.wg and Pa, and the fan air power and shaft power.
How to use it
- Enter the airflow and pick its unit and the pressure unit you want to work in.
- Enter the longest duct run and the friction rate (pressure per 100 ft, or per metre in metric). 0.08–0.10 in.wg/100 ft (about 1 Pa/m) is a common design target.
- Set a fittings allowance as a percentage of the straight-duct friction, then the filter, coil, grille and other pressure drops. Use the filter's dirty (final) pressure drop so the fan still delivers when it loads up.
- Optionally add a design margin and fan efficiency to get power.
The maths
Total static pressure = duct friction + fittings + filter + coil + grille + other. Duct friction is the friction rate times the run length. Fan air power is airflow × pressure; shaft power divides that by the fan efficiency. 1 in.wg = 249.09 Pa.
Limits
This is a quick estimate along the single longest run, not a full duct-sizing calculation. It uses static pressure only, ignores velocity pressure and system effect losses, and expects pressure drops from manufacturers' data for each component.
Privacy
Everything runs in your browser — nothing you enter is sent anywhere.
Related tools
Check air speed with the Duct Velocity Calculator, or the friction rate with the Duct Friction Rate Calculator.