Getting Started

Build your first duct system in under five minutes.

What DuctStatic Does

DuctStatic calculates the total pressure loss through an HVAC duct system, including straight runs, fittings, and transitions. It identifies the critical path, which is the branch with the highest resistance. That number is what your fan has to overcome.

It uses the same underlying physics as professional design tools, without the cost or complexity.

Quick Start Workflow

  1. Set air conditions. Enter your site altitude and design air temperature. These affect air density and viscosity, which feed every calculation downstream.
  2. Add segments. Each segment is one straight run of duct. Give it a length, airflow (CFM), duct shape (round or rectangular), dimensions, and material. See Duct Segments for details.
  3. Add fittings to segments. Elbows, tees, reducers, and transitions attach to the segment they're part of. See Fittings.
  4. Define paths. A path is a chain of segments from the fan to a terminal (diffuser, register, etc.). You can define multiple paths for multi-branch systems.
  5. Run the calculation. Hit Calculate. Results appear instantly. The critical path is highlighted.
  6. Apply a safety factor. Add a percentage buffer to the critical path loss before specifying your fan. 10-15% is typical.
Tip: You don't need an account to use the calculator. Sign up if you want to save and reload your work.

System Requirements

DuctStatic runs entirely in your browser, no installation or plugins required. Any modern desktop browser works. Mobile is supported but the diagram view is easier on a larger screen.

Unit System

The tool works in Imperial units (CFM, inches, feet, in. w.g.).

Duct Segments →