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Rectangular Duct Area

Use the Rectangular Duct Area for hvac planning. Enter Duct width (in) and Duct height (in) to get a clear result, formula explanation, and practical checks.

Rectangular Duct Area measurements

Enter your values, then calculate.

Result

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How to calculate rectangular duct area

This calculator finds the cross-sectional area of a rectangular duct from its width and height.

How the calculation works

Duct area = (Width × Height) ÷ 144, converting square inches to square feet.

Example

A 12 x 8 inch duct: (12×8)÷144 = 96÷144 ≈ 0.667 sq ft.

Frequently asked questions

How is Result calculated?

Result = ([Duct width] × [Duct height]) ÷ 144.

Is the Rectangular Duct Area free to use?

Yes — every calculator on Simple Calculator Tools is free, runs in your browser, and does not require an account.

Quick Insight

Rectangular Duct Area

Duct area = (Width × Height) ÷ 144, converting square inches to square feet.

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Your personalized explanation

Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.

Pro Tips for Rectangular Duct Area

  1. This area feeds into airflow velocity calculations (CFM ÷ area = velocity) for duct sizing and system design.
  2. Keep width and height both in inches before dividing by 144 to convert to square feet.

Common Rectangular Duct Area Mistakes to Avoid

  • Forgetting to divide by 144 to convert from square inches to square feet, leaving the result in the wrong unit for typical HVAC calculations.

When to Use This Calculator

This calculator finds the cross-sectional area of a rectangular duct from its width and height.

Content reviewed: August 2026 · Robert Threadgill
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