The Duct Volume Calculator figures out how much space is inside a duct. It tells you the volume in cubic feet or cubic meters, based on the duct’s size and length. This is great for real-life decisions, like sizing fans, planning airflow, or figuring out how much material fits inside.
This calculator ensures your system matches your needs, whether for heating, cooling, or ventilation. It’s reliable for important tasks, like improving efficiency or meeting building codes. Want to know how it’s calculated? Let’s check out the formula next.
Formula for Duct Volume
The formula for finding duct volume is simple:
V = A × L
Where:
- V = Duct volume (cubic feet or cubic meters)
- A = Duct cross-sectional area (square feet or square meters)
- L = Duct length (feet or meters)
Area for Circular Ducts
For round ducts:
A = π × D²/4
Where:
- D = Duct diameter (feet or meters)
- π = 3.14159
Area for Rectangular Ducts
For rectangular ducts:
A = W × H
Where:
- W = Duct width (feet or meters)
- H = Duct height (feet or meters)
This formula comes from basic geometry. Use the same units—like feet or meters—for all measurements to keep it accurate. Now, let’s make it easier with a table.
Quick Reference Table for Duct Volume
Why calculate every time? This table shows volumes for common duct sizes and lengths. It’s a fast way to check without doing math.
| Duct Type | Size (ft) | Length (ft) | Volume (cu ft) |
|---|---|---|---|
| Circular | 1 (diameter) | 10 | 7.85 |
| Circular | 0.5 (diameter) | 15 | 2.94 |
| Rectangular | 1×0.5 | 20 | 10 |
| Rectangular | 2×1 | 12 | 24 |
How to Use the Table
- Pick your duct type and size.
- Find the length.
- Check the volume in cubic feet.
This table helps with searches like “volume of 1 ft diameter duct.” For exact results, use the formula. Next, let’s try an example.
Example of Duct Volume Calculator
Suppose you have a rectangular duct that’s 2 feet wide, 1 foot high, and 15 feet long. You want to know the volume. Here’s how to do it:
- Calculate the area:
A = W × H
A = 2 × 1 = 2 ft² - Plug into the formula:
V = A × L
V = 2 × 15 = 30 cu ft
So, the duct volume is 30 cubic feet. This matches standard calculations and helps you plan your system.
Most Common FAQs
Volume helps you size fans, plan airflow, or figure out how much air the duct can hold.
Yes, just use the right area formula—π × D²/4 for round ducts, W × H for rectangular.
The formula works the same—just keep all units in meters for cubic meters.