Duct Calculator Elite vs Digiduct

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. One price — no subscriptions, no ads, no accounts. THREE CALCULATORS, ONE TAP APART • DUCT SIZE BY AIRFLOW — Set airflow and either velocity or friction, and solve for round and rectangular duct dimensions. Specify the rectangular aspect ratio to match your available space. The nearest standard round and rectangular sizes are shown with the friction they actually run at. • DUCT SIZE BY DIMENSION — Enter a round diameter or rectangular height and width, then lock airflow, velocity, or friction and solve for the remaining variables. • PRESSURE DROP — Convert between duct length, pressure drop, and friction. Find the exact pressure drop of a given installation, or the maximum duct length that maintains your design pressure drop. DESIGN TOOLS • FRICTION RATE — Enter your available static pressure and duct run, add fittings from a built-in list of typical equivalent lengths (elbows, tees, wyes, supply boots), and get your total effective length and target friction rate — the Manual D style residential design workflow. Then send the result straight into Duct Size by Airflow with one tap. • AIRFLOW FROM HEAT LOAD — Enter a sensible heat load and temperature difference to get the required airflow, corrected for air density. ENGINEERING-GRADE MATH Solves the Colebrook friction-factor equation directly for each duct material's surface roughness — the same method behind the ASHRAE friction chart — rather than interpolating from lookup tables. Roughness values come from Table 1 of the 2025 ASHRAE Handbook — Fundamentals, and the app shows you the one it used. Rectangular results use the Huebscher equivalent-diameter equation; air density is corrected for your temperature and elevation, and air viscosity for your temperature, so results hold up at altitude and outside room temperature. Below the turbulent range where the published methods agree, results are flagged as approximate. PRECISE ENTRY, BUILT FOR THE FIELD Type exact values directly in place — no cumbersome sliders, no pop-up entry screens. Confirm with a tap and every dependent value recalculates instantly. A clean layout keeps every result in view as you work, and everything runs fully offline. CONFIGURED FOR REAL JOB CONDITIONS • Duct dimensions: inches, centimeters, or millimeters • Airflow: CFM, cubic feet per second, cubic meters per second, cubic meters per hour, or liters per second • Velocity: feet per second, feet per minute, or meters per second • Pressure loss: inches of water per 100 ft or pascals per meter • Duct materials: galvanized steel, spiral steel, galvanized spiral (corrugated), aluminum, uncoated carbon steel, PVC plastic pipe, concrete, phenolic duct (pre-insulated), flexible duct (metallic), flexible duct (helix core, insulated), fibrous glass liner (spray coated), and fibrous glass liner (faced, smooth) • Air temperature (°F, °C, K) and elevation (feet or meters) corrections The next time you head to a meeting or out to the job site, leave the ductulator at home — everything you need is on your iPhone or iPad. Questions or ideas for the next version? Email techsupport@cyberprodigy.com — we read every message.

The Digiduct app is a powerful tool designed for HVAC professionals, supporting everything from design calculations to real-time field verification. Built utilizing the equations and recommendations from the ASHRAE Fundamentals – Duct Design chapter, it ensures your calculations are accurate and reliable, saving you time and reducing errors. Key Features: • Multiple Shape Sizing Options: Supports sizing for rectangular, round, and flat oval ducts, offering flexibility for various duct designs. • Customizable Dimensions: For rectangular and oval ducts, users can lock in one dimension, and the app calculates the other, ensuring precise results based on CFM, pressure drop due to friction, or velocity. • Duct Location Intelligence: offers the user predefined parameters to use as starting point and reference when selecting duct sizes so users at HVAC experience level can make confident selections. Why Choose Digiduct? Unlike other duct sizing tools, Digiduct goes above and beyond. It doesn’t just provide basic size outputs—it evaluates the location and context of your duct (high-pressure vs. low-pressure, shaft vs. plenum), alerting you if your selection exceeds maximum pressure drop or velocity limits. This added layer of intelligence ensures higher accuracy and gives users confidence that their sizing is optimal for the application. Get the assurance of precision with Digiduct—designed to meet the demands of real-world HVAC scenarios.