HVAC Duct Sizer Pro

HVAC Duct Sizer Pro is the digital Ductulator built for HVAC engineers and contractors who need accurate duct sizing on the spot — no signal required, no subscription, no clutter. Every calculation runs instantly on your device, based on the same ASHRAE Fundamentals formulas used in professional duct design: Colebrook-White friction factor, Darcy-Weisbach pressure loss, and the Huebscher rectangular-equivalent method. SIZE A DUCT Enter your airflow plus a target friction rate or velocity, and get: • Recommended round duct diameter — exact and nearest standard size • Rectangular equivalent (equal-friction, Huebscher method) • Resulting velocity, friction rate, and Reynolds number ANALYZE AN EXISTING DUCT Already have a duct in place? Enter the airflow and its dimensions (round or rectangular) to instantly get velocity, friction rate, velocity pressure, and Reynolds number. BUILT FOR THE FIELD • 100% offline — works anywhere, with zero setup • SI and Imperial units, switchable anytime, with independent airflow unit (L/s, m³/h, CFM) • Five duct material roughness presets, from smooth PVC to fully-extended flex • Standard or custom air density • Numeric keypad or system keyboard input, with live recalculation on every keystroke • Available in English, 日本語, 简体中文, 한국어, Français, Deutsch, Español, and Tiếng Việt NO SUBSCRIPTIONS. NO ADS. NO ACCOUNT. HVAC Duct Sizer Pro is a one-time purchase. Buy it once, use it forever — on every job, offline. From the makers of AirCalc Pro, the psychrometric calculator trusted by HVAC professionals.