# HVAC Calc – Duct & Airflow — Duct sizing • friction • PDF > Offline HVAC duct sizing, airflow, and friction loss calculator with PDF reports. (iPhone/iPad app by NURDAN ARI.) - Source: https://appshunter.io/ios/app/hvac-calc-duct-and-airflow/id6751240306 (this page in markdown: same URL + `.md`) - Developer: [NURDAN ARI](https://appshunter.io/developer/1833674718) - Category: Utilities, Productivity - Price: Free - Rating: 5.00/5 from 2 App Store ratings · 2 written reviews indexed - Age rating: 17+ - Requires: iOS 16.0 · 6 MB - Languages: English - Released: 2025-08-20 - Data updated: 2026-06-10 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/hvac-calc-duct-and-airflow/id6751240306/reviews.md ## What is HVAC Calc? Tired of complex charts and formulas on the job site? Air Duct Calc is your all-in-one HVAC toolkit, designed to give you instant answers without an internet connection. Simplify your workflow and get accurate results in seconds. YOUR FIELD CALCULATIONS, SIMPLIFIED: ▶ Instant Duct Sizing Forget the manual work. Input your airflow and velocity to get precise circular and rectangular duct dimensions instantly. ▶ One-Tap Airflow & Velocity Working with existing ducts? Enter the area to immediately calculate the airflow in both CFM and L/s. ▶ Accurate Friction Loss Based on the Darcy-Weisbach formula, get reliable friction loss data (Pa/m & in.wg/100 ft) to ensure your system is designed correctly. ▶ Essential Conversion Tools * Rectangular to Circular: Seamlessly find the equivalent hydraulic diameter for any duct. * SI & Imperial: Switch between metric and imperial units on the fly. BUILT FOR THE REAL WORLD: * 100% Offline Functionality: Perfect for basements, new constructions, and areas with no signal. * PDF Report Generator: Quickly create and share professional PDF reports of your calculations. * Clean & Fast Interface: No clutter. Just the tools you need, right when you need them. Whether you're an engineer, a technician, or a student, Air Duct Calc is the essential tool to make your job easier. Download now! HVAC Calc brings the essential duct & airflow math to your phone—offline and on site. * Duct Sizing: diameter from Q & V; rectangular area/velocity and equivalent (ASHRAE) * Airflow: velocity + area → flow (L/s & CFM side-by-side) * Rect ↔ Circ: equivalent circular & hydraulic diameter (4A/P) * Friction Loss: Darcy–Weisbach with Swamee–Jain (Pa/m & in.wg/100 ft) * Psychrometrics: dew point (Magnus) * PDF Expert: Images → PDF, plus HVAC report generator & viewer * Units: instant SI/Imperial toggle * Design: polished dark UI built with SwiftUI ## Key features - Instant duct sizing - Airflow and velocity calculation - Friction loss calculation - Rectangular to circular duct conversion - SI and Imperial unit toggle - Offline functionality - PDF report generator ## Recent user reviews (2 of 2) All indexed reviews: https://appshunter.io/ios/app/hvac-calc-duct-and-airflow/id6751240306/reviews.md ### 5/5 — Excellent HVAC Tool for On-Site Use *2025-09-07* I’m really impressed with HVAC Calc – Duct & Airflow—a true field-ready app for engineers and technicians. The duct sizing tool is spot-on: just input your airflow and velocity, and it instantly gives you both circular and rectangular dimensions. The airflow and friction loss calculators (using Darcy-Weisbach formula) are fast and accurate—even if you’re working completely offline on the job site. Love the PDF report generator for sharing neat, professional summaries. Compact, reliable, and highly recommended for anyone needing quick HVAC calculations. ### 5/5 — duct airflow calculator app *2025-08-24* duct airflow calculator app ## Frequently asked questions about HVAC Calc ### Does HVAC Calc have ads? No, HVAC Calc is completely ad-free, allowing for an uninterrupted user experience during critical on-site calculations. ### How often is HVAC Calc updated? HVAC Calc was last updated on September 16, 2025, with version 1.0.4. This indicates a commitment to ongoing improvements and bug fixes. ### What devices support HVAC Calc? Currently, HVAC Calc is supported on iPhones. Future updates may expand compatibility to other devices. ### Is HVAC Calc suitable for beginners? Yes, HVAC Calc is designed to simplify complex charts and formulas, making it accessible for students and technicians new to HVAC calculations. ### Can I use HVAC Calc without an internet connection? Absolutely. HVAC Calc offers 100% offline functionality, making it ideal for use in basements, new constructions, or any location with limited or no signal. ### What is the age rating for HVAC Calc? HVAC Calc has an age rating of 17+, suggesting it contains content or complexity suitable for mature users, likely due to its technical nature. ### How does HVAC Calc handle unit conversions? HVAC Calc allows for instant switching between SI and Imperial units on the fly, ensuring flexibility for users working with different measurement systems. ### What kind of reports can HVAC Calc generate? HVAC Calc can generate professional PDF reports of your calculations, which can be quickly created and shared directly from the app. ## Version history (last 3 releases) ### 1.0.4 — 2025-09-16 Air Duct Calc is your all-in-one HVAC toolkit, designed to give you instant answers without an internet connection. Fixed Pdf Export. ### 1.0.1 — 2025-08-25 Fixed Design UI. ### 1.0 — 2025-08-20 No release notes. ## More apps by NURDAN ARI - [LoFi Music: Chill & Focus](https://appshunter.io/ios/app/lofi-music-chill-and-focus/id6751145195) - [Anime Jigsaw: Waifu Puzzles](https://appshunter.io/ios/app/anime-jigsaw-waifu-puzzles/id6751961511) All apps by NURDAN ARI: https://appshunter.io/developer/1833674718 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*