# Duct-Fit > Duct size selection tool for HVAC professionals and engineers. (iPhone/iPad app by Izumi Consulting,Inc..) - Source: https://appshunter.io/ios/app/duct-fit/id735908922 (this page in markdown: same URL + `.md`) - Developer: [Izumi Consulting,Inc.](https://appshunter.io/developer/735908925) - Category: Utilities, Business - Price: Free - Age rating: 4+ - Requires: iOS 11.4 · 3 MB - Languages: Japanese - Released: 2013-11-08 - Data updated: 2026-07-31 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/duct-fit/id735908922/reviews.md ## What is Duct? 『Duct-Fit』は、直感的に分かりやすいデザインと単純な操作で、ダクトサイズを選定出来るアプリです。 　「風量」「基準静圧」「風速」を基に適正なダクトサイズの算出が可能です。 特徴 　・選定したダクト形状を図形で表示することにより、ダクトイメージが付きやすい設計になっています。 　・「角ダクト」だけでなく「丸ダクト」のダクトサイズ算出にも対応してます。 　・「アスペクト比」や「風速」に目安となる「警告値」を任意で設定できます。 　・「アスペクト比」や「風速」に計算可能な上限としての「上限値」を任意で設定できます。 　・「基準静圧」は「初期値」として任意で通常使う値を設定することができます。 　・ダクトサイズの選定については、「コールブルックの式」及び「ダルシー・ワイズバッハ式」により、選定しております。 ## Key features - Intuitive design for easy duct size selection - Calculates duct size based on airflow, static pressure, and velocity - Supports both rectangular and round ducts - Visual representation of selected duct shapes - Customizable warning and upper limits for aspect ratio and air velocity - Set default standard static pressure ## Recent user reviews (5 of 5) All indexed reviews: https://appshunter.io/ios/app/duct-fit/id735908922/reviews.md ### 5/5 — これは *2017-04-10, version 1.2.0* ええね ### 5/5 — 便利 *2013-11-20, version 1.0.1* 次も楽しみにしてます‼ ### 5/5 — 便利 *2013-11-20, version 1.0.1* このアプリはありがたいです。 ### 5/5 — 使いやすい！ *2013-11-11, version 1.0* 使いやすい！ ### 5/5 — 分かりやすい *2013-11-09, version 1.0* ダクトの形もが変わって面白い。 ## Frequently asked questions about Duct ### What is Duct-Fit used for? Duct-Fit is a utility app designed to help users select appropriate duct sizes. It calculates these sizes based on key parameters like airflow, standard static pressure, and air velocity, making the process more efficient for HVAC professionals. ### Does Duct-Fit support different duct shapes? Yes, Duct-Fit supports the calculation of duct sizes for both '角ダクト' (rectangular ducts) and '丸ダクト' (round ducts), offering versatility for various project needs. ### Can I set custom limits in Duct-Fit? Yes, you can set optional '警告値' (warning values) and '上限値' (upper limits) for 'アスペクト比' (aspect ratio) and '風速' (air velocity). This allows for customized design parameters and checks. ### How does Duct-Fit calculate duct sizes? Duct-Fit uses established engineering formulas, specifically the 'コールブルックの式' (Colebrook equation) and 'ダルシー・ワイズバッハ式' (Darcy-Weisbach equation), to determine the appropriate duct sizes. ### Is Duct-Fit available on multiple devices? Duct-Fit is available for iPhone, iPad, and iPod devices, allowing users to access its features across various Apple mobile platforms. ### How often is Duct-Fit updated? The latest version of Duct-Fit is 1.3.0, which was last updated on June 4, 2020. While updates may not be frequent, the app provides core functionality for duct sizing. ### Does Duct-Fit have ads? No, Duct-Fit is ad-free, providing an uninterrupted user experience for its utility functions. ### What is the age rating for Duct-Fit? Duct-Fit has an age rating of 4+, indicating it is suitable for a wide range of users, including younger individuals who may be learning about HVAC concepts. ## Version history (last 5 releases) ### 1.3.0 — 2020-06-04 広告バナーの更新 ### 1.2.0 — 2016-07-06 広告画像の追加 ### 1.1.0 — 2016-04-27 バナー広告等の変更 ### 1.0.1 — 2013-11-18 UI表示の最適化 ### 1.0 — 2013-11-08 No release notes. --- *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 2026-07-31.*