Duct CFM to Diameter: 100 CFM at 500 FPM
Specific conversion page with reference context, calculator, and nearby values.
On this page
100 CFM at 500 FPM converts to
6.06 in round duct
Use this as a quick reference for Duct CFM to Diameter.
Value Details
Input: 100 CFM at 500 FPM
Output: 6.06 in round duct
Browse all reference values for Duct CFM to Diameter
velocityFpm: 500 | areaFt2: 0.2 | nominalDiameterIn: 6
Duct CFM to Diameter Calculator
Estimate a round duct diameter from airflow and target velocity.
Estimated Round Diameter
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Nearby Reference Values
| Airflow Scenario | Calculated Diameter | Area (ft²) | Nominal (in) |
|---|---|---|---|
| 100 CFM at 500 FPM | 6.06 in round duct | 0.2 | 6 |
| 100 CFM at 700 FPM | 5.12 in round duct | 0.143 | 5 |
| 100 CFM at 900 FPM | 4.51 in round duct | 0.111 | 5 |
| 100 CFM at 1100 FPM | 4.08 in round duct | 0.091 | 4 |
| 150 CFM at 500 FPM | 7.42 in round duct | 0.3 | 7 |
| 150 CFM at 700 FPM | 6.27 in round duct | 0.214 | 6 |
Frequently Asked Questions
Common questions about Duct CFM to Diameter, formulas, and expected usage.
How is round duct diameter estimated from CFM?
The calculator first finds area from CFM/velocity, then solves the round-duct area formula for diameter.
Why does velocity affect duct size?
Higher design velocity allows smaller ducts for the same airflow, while lower velocity requires larger ducts.
What velocity should I choose?
Choose based on noise, pressure drop, and system type. Main trunks often use lower velocity than small branch runs.
Is this enough for full duct design?
Use it for quick sizing; complete designs should include friction, fittings, static pressure, and equipment constraints.
Methodology and Review
This page is generated from the same conversion definition used by the main calculator page, which keeps the calculator, reference table rows, and FAQ schema aligned.
Reviewer and update metadata are shown above and included in structured data. See our editorial policy, review process, and corrections policy.
Use this page as a fast lookup reference, then confirm final project values using applicable standards and manufacturer documentation.