Who is the HVAC Duct Sizing Calculator for?

It is built for HVAC contractors who need fast, accurate results for size ducts quickly during estimating.

How do I use the HVAC Duct Sizing Calculator?

Enter CFM Set velocity target Review duct dimensions

Is this a Manual D tool?

It is a fast sizing estimator, not a full Manual D.

Can I use it for commercial jobs?

Yes. Enter the required airflow to size ducts.

Is this tool free to use?

Yes. This tool is free and designed for quick, practical results.

Does this work for projects nationwide?

Yes. It uses standard construction inputs used across the US.

HVAC Duct Sizing Calculator

Size ducts for proper airflow and velocity.

Airflow Requirements

Airflow (CFM)

Total Cubic Feet per Minute needed for the room/zone.

Friction Rate (IWC/100')

Design friction rate (Inches Water Column per 100ft).

Recommended Duct Size

Round Duct

0" ø

Exact: 0.0"

Square Equivalent

Approximate square duct

Performance Check

Air Velocity

0 FPM

Velocity is within standard residential limits (<900 FPM).

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HVAC Duct Sizing Calculator for HVAC contractors

HVAC Duct Sizing Calculator helps HVAC contractors size ducts quickly during estimating. Enter CFM and velocity targets and get duct size recommendations you can use immediately in your bid or project file.

Used by contractors across California, Texas, Florida, New York, and Illinois, with active users in Los Angeles, Houston, Dallas, Chicago, Phoenix, Atlanta, Seattle, and Denver.

Quick answer: what does this tool do?

Calculate duct sizes based on airflow and velocity.

How should I apply the results?

Use sizes for takeoffs and equipment coordination.

Is this suitable for public bids?

Yes. The inputs align with typical DOT, municipal, and federal bid requirements.

What keywords does this tool target?

HVAC duct size calculator, duct CFM calculator

The HVAC Duct Sizing Calculator gives fast, reliable results for HVAC contractors to size ducts quickly during estimating. Enter CFM and velocity targetsand get duct size recommendations in minutes.

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