Duct Calculator Elite™
Replace your ductulator wheel — fast, precise duct sizing built on ASHRAE friction-loss equations.
HVAC
Duct Calculator Elite™ replaces your ductulator wheel with fast, precise duct sizing built on the friction-loss equations of the ASHRAE Handbook — Fundamentals. Trusted by HVAC professionals, mechanical engineers, and contractors since 2013.
Type exact values directly in place — no cumbersome sliders, no pop-up entry screens. Confirm with a tap and every dependent value recalculates instantly, with results kept on screen as you work. Everything runs fully offline.
One price — no subscriptions, no ads, no accounts.
Available for iOS (iPhone & iPad) and Android.
Features
Calculators
- Duct size by airflow — set airflow plus velocity or friction; solve round and rectangular dimensions with your choice of aspect ratio
- Duct size by dimension — enter a round diameter or rectangular height × width, lock airflow, velocity, or friction, and solve the rest
- Pressure drop — convert between duct length, pressure drop, and friction to check any installation
- Friction rate — a Manual D–style design workflow: enter available static pressure and duct run, add fittings from a built-in equivalent-length list, and get total effective length and target friction rate — then send it into duct sizing with one tap
- Airflow from heat load — enter a sensible heat load and temperature difference to get required airflow, corrected for air density
Engineering & units
- Solves the Colebrook friction-factor equation directly for each duct material's surface roughness — the same method behind the ASHRAE friction chart
- Rectangular results use the Huebscher equivalent-diameter equation, with air density corrected for temperature and elevation
- Duct dimensions in inches, cm, or mm; airflow in CFM, CFS, m³/s, or L/s; velocity in ft/s, ft/min, or m/s; pressure loss in inH₂O/100 ft or Pa/m
- 9 duct materials: galvanized steel, spiral steel, aluminum, flexible metallic duct, fibrous glass liner, smooth liner, uncoated carbon steel, PVC, and concrete
- Available in English, Spanish, French, German, Portuguese, Japanese, Korean, and Chinese
See it in action
Get Duct Calculator Elite™ today
Available for iOS (iPhone & iPad) and Android. Free technical support included.