100 mm
- Inside diameter
- 100 mm
- Airflow
- 0.023562 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
VALICALC · TECHNICAL REFERENCE
Round Duct CFM Chart
Look up round-duct airflow at an editable mean velocity, compare metric and inch diameters, and continue with a straight-duct loss calculation.
SCENARIO MATRIX
Search within the verified subset. Numeric sizes match complete designations; a nearby size is a candidate, not an exact match.
SELECTED REFERENCE
200 mm
- Inside diameter
- 200 mm
- Airflow
- 0.094248 m³/s
- Selected velocity
- 3 m/s
All fields & cell provenance
- Example series
- Metric
- Duct example: Duct area and airflow relationship — Authored circular continuity example · verified 2026-10-06 · source value 200 mm.
- Inside diameter: Duct area and airflow relationship — Authored circular continuity example · verified 2026-10-06 · source value 200.
- Airflow: Duct area and airflow relationship — Authored circular continuity example · verified 2026-10-06.
- Selected velocity: Duct area and airflow relationship — Authored circular continuity example · verified 2026-10-06 · source value 3.
- Example series: Duct area and airflow relationship — Authored circular continuity example · verified 2026-10-06 · source value Metric.
v1.2.0 · verified 2026-10-06 · values use the valid conditions shown above
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Duct Size Calculator →200 mm200 mmBack to answer ↑
Explore the verified data
18 matching rows · 18 in this subset
| Duct example | Inside diameter | Airflow | Selected velocity | Actions |
|---|---|---|---|---|
| 100 mm | 100 mm | 0.023562 m³/s | 3 m/s | |
| 4 in | 101.6 mm | 0.024322 m³/s | 3 m/s | |
| 125 mm | 125 mm | 0.036816 m³/s | 3 m/s | |
| 150 mm | 150 mm | 0.053014 m³/s | 3 m/s | |
| 6 in | 152.4 mm | 0.054724 m³/s | 3 m/s | |
| 160 mm | 160 mm | 0.060319 m³/s | 3 m/s | |
| 200 mm | 200 mm | 0.094248 m³/s | 3 m/s | |
| 8 in | 203.2 mm | 0.097288 m³/s | 3 m/s | |
| 250 mm | 250 mm | 0.147262 m³/s | 3 m/s | |
| 10 in | 254 mm | 0.152012 m³/s | 3 m/s | |
| 300 mm | 300 mm | 0.212058 m³/s | 3 m/s | |
| 12 in | 304.8 mm | 0.218898 m³/s | 3 m/s | |
| 315 mm | 315 mm | 0.233793 m³/s | 3 m/s | |
| 14 in | 355.6 mm | 0.297944 m³/s | 3 m/s | |
| 400 mm | 400 mm | 0.376991 m³/s | 3 m/s | |
| 16 in | 406.4 mm | 0.389151 m³/s | 3 m/s | |
| 500 mm | 500 mm | 0.589049 m³/s | 3 m/s | |
| 20 in | 508 mm | 0.608049 m³/s | 3 m/s |
4 in
- Inside diameter
- 101.6 mm
- Airflow
- 0.024322 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
125 mm
- Inside diameter
- 125 mm
- Airflow
- 0.036816 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
150 mm
- Inside diameter
- 150 mm
- Airflow
- 0.053014 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
6 in
- Inside diameter
- 152.4 mm
- Airflow
- 0.054724 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
160 mm
- Inside diameter
- 160 mm
- Airflow
- 0.060319 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
200 mm
- Inside diameter
- 200 mm
- Airflow
- 0.094248 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
8 in
- Inside diameter
- 203.2 mm
- Airflow
- 0.097288 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
250 mm
- Inside diameter
- 250 mm
- Airflow
- 0.147262 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
10 in
- Inside diameter
- 254 mm
- Airflow
- 0.152012 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
300 mm
- Inside diameter
- 300 mm
- Airflow
- 0.212058 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
12 in
- Inside diameter
- 304.8 mm
- Airflow
- 0.218898 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
315 mm
- Inside diameter
- 315 mm
- Airflow
- 0.233793 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
14 in
- Inside diameter
- 355.6 mm
- Airflow
- 0.297944 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
400 mm
- Inside diameter
- 400 mm
- Airflow
- 0.376991 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
16 in
- Inside diameter
- 406.4 mm
- Airflow
- 0.389151 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
500 mm
- Inside diameter
- 500 mm
- Airflow
- 0.589049 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Metric
20 in
- Inside diameter
- 508 mm
- Airflow
- 0.608049 m³/s
- Selected velocity
- 3 m/s
More dimensions
- Example series
- Inch
How to use this data
A=π(D/1000)²/4 m²; Q=Av. Display conversions: 1 CFM=0.0004719474432 m³/s. Metric and inch example series are distinct.
CHECK THE METHOD
Worked example
At 200 mm and 3 m/s, Q≈0.0942478 m³/s or 199.70 CFM.
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Common lookup questions
Can I use these values as a universal specification?
A diameter does not establish a universal CFM capacity. Actual usable bore, roughness, fittings, fan pressure and noise limits need separate checks.
TRACEABLE DATA
Sources, scope & verification
Dataset v1.2.0
Last verified:
18 authored inside-diameter examples. Airflow is conditional on velocity; this is not a pressure/friction capacity rating.
Values are curated product facts or generated scenarios. Paid standards, complete catalogs and source diagrams are not reproduced. A verification date applies to this documented subset.
Duct area and airflow relationship ↗
Type A · Greenheck · Options, Accessories and Engineering, October 2021, ACC-34
Original generated scenarios from the stated equations; source tables/text/drawings are not reproduced.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- authored-formula
- Artifact SHA-256
- No retained source artifact hash; see the stated source and verification record.