DuctPro vs Easy Duct

DuctPro is the professional HVAC duct sizing calculator built for field technicians and MEP engineers. Get engineering-grade results in seconds — offline, no subscription. RESULTS IN 3 TAPS Enter airflow, select duct type, get the size. Round, rectangular, flat oval, and flexible ducts. Size by friction rate or air velocity. A color-coded performance badge tells you instantly if your duct is optimal, too fast, too slow, or at risk. ENGINEERING-GRADE ENGINE Calculations use the Darcy-Weisbach friction equation with Colebrook-White solver — the industry-standard method for duct design. Nine material types with published roughness values: galvanized steel (spiral & rectangular), flexible duct (metallic & non-metallic), fiberglass duct board, fibrous glass liner, PVC, aluminum, and concrete. FITTINGS & PRESSURE DROP Calculate total system pressure drop including straight run and all fittings. Ten fitting types with industry-standard loss coefficients: 90° and 45° elbows (round and rectangular), mitered elbow, tee branch and straight-through, concentric reduction, enlargement, and butterfly damper. PRO MODE Unlock full 2D lookup tables for rectangular elbows and concentric reductions, plus A/B ratio selector for flat oval ducts. Bilinear interpolation for accurate results at any H/W or area-ratio geometry. ORGANIZE YOUR WORK Save calculations with a custom name and notes. Group them into color-coded projects. Export individual calculations as text or PDF, and full projects as CSV. Search your entire history in one tap. IMPERIAL & METRIC Switch between I-P and SI units at any time. All inputs and outputs update instantly across every screen. I-P: CFM · in · ft/min · inWC/100ft SI: L/s · mm · m/s · Pa/m 6 LANGUAGES English · Français · Español · Português · Deutsch · Italiano — 100% offline. No account. No subscription. —

Easy Duct is an air duct sizing calculator built by an HVAC engineer for real design work. Enter what you know and get a buildable duct size in seconds, on site or at your desk. Easy Duct solves for whatever is missing: airflow, head loss, velocity or duct size. Set a maximum head loss and a maximum velocity together, and the duct is sized to whichever limit is reached first. The governing limit is always named, so you know exactly why you got that size. SIZE THE WAY YOU DESIGN - Head loss and velocity limits checked at the same time - Rectangular and round duct, with aspect ratio shown for every size - Buildable size steps (½, 1 or 2 in) so results match what gets fabricated - EN 1506 standard sizes for metric round duct - Pick any duct size and see its spare capacity live SAFETY FACTOR AND ADD TO FLOW - Apply a flow safety factor that is built into the design flow - Adding a branch or outlet? Type the extra airflow and it goes straight onto the total CROSS-CHECK: TWO SCENARIOS, ONE DUCT Size a single duct against two sets of conditions, such as normal and peak operation. Link Scenario B to Scenario A by percentage, added value, equal or absolute, and see side-by-side results with the scenario that governs named up front. UNITS YOUR WAY - Switch between IP and SI with one tap - Tap any unit to change it, field by field: a mm duct with L/s or cfm airflow is fine ENGINEERING YOU CAN CHECK - Darcy-Weisbach with your choice of friction model: Colebrook, Haaland or Altshul - Duct wall roughness by material - Air density and viscosity from temperature and altitude - Full results: design flow, velocity, head loss, equivalent diameter, required round size, cross-section, Reynolds number, friction factor and velocity pressure SIMPLE AND FAST - Minimal interface with results that fold away until you need them - Works fully offline - Also available on Windows and Android Easy Duct is for HVAC and mechanical engineers, designers, estimators and students who size ductwork every day and want a quick, reliable answer.