Flex Ductulator


Welcome to our online Flex Duct Ductulator! Our tool is designed to simplify your ductwork calculations and make your projects more efficient. With just a few clicks, you can determine the perfect duct size and airflow for any space, ensuring optimal performance and comfort. Let’s get started and make your next HVAC project a breeze!

Flex Ductulator
Required Duct Size: 6 inches


  • Most contractors use an average of 0.05 to 0.08 friction loss.
  • The average design air velocity can range between 700 to 900 fpm.
  • These are just recommendations, always consult with your design team.


  • Always stretch ductwork close to a 4% compression
  • Avoid sharp turns, always allow for wide 90° air duct turns
  • Flexible ducts shall be supported at intervals not exceeding 4 feet (1219 mm) and at each change of direction.
  • Use appropriate hangers and straps that do not compress or damage the ductwork.
  • Ensure all ducts are properly sealed to prevent air leaks.
  • There should be a minimum of 1 inch (25 mm) clearance between ducts, this allows for proper air circulation and prevents condensation between the ducts.