# Duct Calculator — user reviews > 17 indexed App Store user reviews of Duct Calculator by Pheinex, LLC, rated 4.50/5 from 188 ratings. - Source: https://appshunter.io/ios/app/duct-calculator/id1078238132/reviews - App overview in markdown: https://appshunter.io/ios/app/duct-calculator/id1078238132.md - Rating breakdown: 5★ 151 · 4★ 15 · 3★ 7 · 2★ 3 · 1★ 12 ## Most critical reviews (10 lowest-rated) ### 1/5 — Really mot good app . *2023-07-05* Calculation are not acure , not integral proximity in calculations ### 1/5 — Not accurate *2022-05-03* I was trying to find an app for the convenience of not carrying several sliders around in a bag, I just have everything in one place. But the interface isn’t easy to use or quick, and non of the numbers are adding up to any duct calculator I have or have access to. I can’t trust any of the numbers and I can’t use something if I can’t trust it. ### 1/5 — Limited *2019-03-12* Not user friendly. Only able to develop some calculations based on single sections of distribution systems. Don’t try to find out existing conditions using this format because duct sizes change as variables are imputed. Very frustrating. ### 1/5 — Useless app *2018-06-11* If I could give this app less than one star, I would! I’m out the money for the app. It’s unusable! Lesson learned!! Look elsewhere. I deleted app sent an email, no response!!! 6/11/18: Finally received an email from developer. Asking if I am having problem using the App. They just don’t get it! The app does not work as described!! I asked for a refund, doesn’t look like that will happen! Again, lesson learned! DON’T PURCHASE THIS APP, IT’S USELESS!!! **Developer response:** We are sorry you did not find the app useful. We have not been able to locate the referenced email. Perhaps there was a delivery error? There is a brief summary of usage here that you may find helpful: https://www.pheinex.com/duct-calculator-faq/ If you would like to contact us, please do so at https://www.pheinex.com/contact/ and we will be glad to see how we can help. ### 1/5 — Weak *2017-09-30* Weak app **Developer response:** Sorry to hear that the app did not meet your expectations. If there are specific issues you are having with the app, or feature recommendations you have, please contact us on our web site at https://www.pheinex.com/contact/ and we will be glad to see if we can help you! ### 2/5 — So less functions and so expensive *2017-12-27* Nothing to say ### 3/5 — Where’s the option for flex duct? *2024-02-08* Not happy with my purchase ### 3/5 — Subscription *2023-05-16* Do I have to pay monthly subscription for this app or just one time pay at the start? ### 4/5 — Almost perfect… but not quite there. *2023-03-17* This thing is great. only 2 things would make it perfect. 1) Flex duct sizing. 2) multiple friction rate fields, so you can select both your return AND supply friction rates at the same time and see output of both. plus have those fields be lockable so you can’t change them by accident. If these changes were made, I would buy this AGAIN and likely so would every consultant in my company. ### 4/5 — Like it *2016-06-01* I like it But i wish i can lock friction rate I hope in next version i can do it ## Most praised reviews (7 highest-rated) ### 5/5 — GREAT APPLICATION *2023-12-02* I've been using it for many years, my go to every day. ### 5/5 — Better than cardboard Ductulator *2022-05-27* It’s a little difficult to get used to the way things work at first, having only used the rotating cardboard Trane ductulators in the past, but once you get used to it it is much more accurate and far easier to obtain correct sizing for very specific lengths and widths of duct. ### 5/5 — Great app. *2021-04-22* I really like the dial format for selecting duct sizes. ### 5/5 — A must have *2020-12-20* This is an excellent tool for on the job calculation. It’s a must have. ### 5/5 — Problems since update *2020-09-21* Latest update seems to be causing velocity errors, 132 l/s on a duct size of 200mm dia should jot be coming up as over 40m/s ?? Please can this be rectified as was a great app before the update **Developer response:** A fix for the velocity display issue has been submitted and approved by Apple. The update should be rolling out soon. You can contact us directly here: https://www.pheinex.com/contact/ ### 5/5 — Best on App Store *2018-11-08* Best duży Calculator in the App Store, easy to use, intuitive. Don’t waste money on anything else. ### 5/5 — Top one *2017-02-02, version 1.1.3* I use this one more often than any other I have, It's great --- *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 2026-08-13.*