# Flow Test Calculator > Hydrant and water system flow rate calculation tool using Hazen-Williams formula. (iPhone/iPad app by Larry Owens.) - Source: https://appshunter.io/ios/app/flow-test-calculator/id853530759 (this page in markdown: same URL + `.md`) - Developer: [Larry Owens](https://appshunter.io/developer/496138296) - Category: Productivity - Price: Free with in-app purchases - Rating: 4.10/5 from 63 App Store ratings · 16 written reviews indexed - Age rating: 4+ - Requires: iOS 14.0 · 2 MB - Languages: American English - Released: 2014-04-18 - Data updated: 2026-06-03 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/flow-test-calculator/id853530759/reviews.md ## What is Flow Test Calculator? This app is a simple flow test calculator to assist the user with determining flow rates of hydrants as well as determining if the maximum flow of the water system. A standard variation of the Hazen-Williams formula is used to determine the Max Flow Available. All units are in Imperial. Metric to come soon. ## Key features - Hydrant flow rate calculation - Maximum water system flow determination - Hazen-Williams formula implementation - Imperial unit support - Future metric unit support ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Disable Purchase Requests | $0.99 | one-time | | Disable Purchase Requests 9.99 | $9.99 | one-time | | Disable Purchase Requests 1.99 | $1.99 | one-time | | Disable Purchase Request 4.99 | $4.99 | one-time | ## Recent user reviews (10 of 16) All indexed reviews: https://appshunter.io/ios/app/flow-test-calculator/id853530759/reviews.md ### 1/5 — iOS 16.3.1 *2023-03-29, version 2.0* Can’t read the results on my iPhone12. It used to work😠 ### 5/5 — NEEDS UDATE!!! *2021-06-24, version 1.0* Great app. Use at work quite often. Tried using it the other day but will not open because it needs new update for the iOS. ### 1/5 — Flow Test Calc *2021-06-22, version 1.0* So I buy the app it doesn’t operate with my phones iOS. You going to support your product with an update ? As for the product itself. I compared flow numbers using a calculator & this app. if the formula is correct they should match. App worked flawlessly easy to use as well as versatile. Could flow 2 1/2” port or 5 1/2” If you update the app I would absolutely give it five stars. If your own products aren’t worth your support. Then don’t look to me to support this or any other products produced by this company. Why should I support a product produced by people that do not care enough to support it themselves? I gave it one star because if you don’t update it is nothing more than a one hit wonder. Which of course makes me wonder “if it’s that way with the app I purchased why would any of the software applications produced by this company be different. “. need an app it’s going to work over a period of time specifically more than six months look somewhere else. “ would be the advise / word of mouth advertising you receive I will support your products with an upgrade of my review if you show your “products” are worth your support ### 5/5 — Update Needed!!! *2021-06-12, version 1.0* The Apple update to 14.6 iSO will not allow the app to open or work. Do ya have plans to work an update so I can keep using your app for my business? While you are there would you consider to auto populate the flow based off the pitot? Not necessary but would be convenient! Please let us know you are planning your update! ### 1/5 — does not work with new update! *2021-06-07, version 1.0* should have read the GD reviews before i paid for it 😬 ### 5/5 — Please update for new iOS *2021-06-07* Can’t use the app unless developer updates to be compatible with new iOS ### 4/5 — Needs update *2021-05-21, version 1.0* This app works great but needs to be updated, hopefully you can make this work again for iOS 14. ### 4/5 — Needs updating to work with iOS 14.5 *2021-05-04, version 1.0* Will not open on an iPhone using iOS 14.5 which is the latest iOS. Hope you can make this work again! Thanks! ### 5/5 — Daily *2021-04-22, version 1.0* I use this app everyday!! Love it!! ### 4/5 — Great App For Calculating Hydrant Flow Pressures *2021-04-01, version 1.0* Great app to use out in the field for fire hydrant flow testing ## Frequently asked questions about Flow Test Calculator ### What is Flow Test Calculator used for? Flow Test Calculator is used to determine the flow rates of hydrants and to assess the maximum flow capacity of a water system. It employs a standard variation of the Hazen-Williams formula for these calculations. ### What units does Flow Test Calculator support? Currently, Flow Test Calculator supports Imperial units for all calculations. The developer has indicated that metric units will be added in a future update. ### How accurate is Flow Test Calculator? Flow Test Calculator has a user rating of 4.1 stars from 63 ratings, suggesting a generally positive user experience and reliable performance for its intended calculations. ### Is Flow Test Calculator available on Android? Based on the provided information, Flow Test Calculator is available on iPhone, iPad, and iPod. Support for Android devices is not specified. ### When was Flow Test Calculator last updated? The latest version of Flow Test Calculator, version 2.0, was last updated on September 1, 2021. The app was initially released on April 18, 2014. ### What is the age rating for Flow Test Calculator? Flow Test Calculator has an age rating of 4+, making it suitable for a wide range of users, including younger individuals who may be learning about water systems. ### Does Flow Test Calculator have ads? No, Flow Test Calculator does not display ads. However, it does offer in-app purchases, which may provide additional features or functionality. ## Version history (last 2 releases) ### 2.0 — 2021-09-01 Changed the layout and made it work on multiple screen sizes. Added the ability to enter default numbers. ### 1.0 — 2014-04-18 No release notes. ## Apps similar to Flow Test Calculator | App | Rating | Price | Category | | --- | --- | --- | --- | | [GERFS - Blue](https://appshunter.io/ios/app/gerfs-blue/id1610736063) | 1.0 (16) | Free | Productivity | | [ScanSeries](https://appshunter.io/ios/app/scanseries/id672855505) | 3.8 (48) | Free | Productivity | | [Xaap](https://appshunter.io/ios/app/xaap/id1378923288) | 4.1 (1,339) | Free | Productivity | | [IAAI](https://appshunter.io/ios/app/iaai/id1588771743) | 5.0 (4) | Free | Productivity | | [NC/SC IAAI Events](https://appshunter.io/ios/app/ncsc-iaai-events/id6467808868) | — | Free | Productivity | | [FormLink](https://appshunter.io/ios/app/formlink/id1622429554) | 4.0 (4) | Free | Productivity | ## More apps by Larry Owens - [EMS Guidebook](https://appshunter.io/ios/app/ems-guidebook/id527102213) - [2022 IRPG](https://appshunter.io/ios/app/2022-irpg/id1617401344) All apps by Larry Owens: https://appshunter.io/developer/496138296 ## Related topics [urflowdig](https://appshunter.io/ios/topics/urflowdig) · [elegant flow](https://appshunter.io/ios/topics/elegant-flow) · [hydrant flow test calculator](https://appshunter.io/ios/topics/hydrant-flow-test-calculator) · [redsea flow](https://appshunter.io/ios/topics/redsea-flow) · [larry owens](https://appshunter.io/ios/topics/larry-owens) · [taylor flows](https://appshunter.io/ios/topics/taylor-flows) · [flow wms](https://appshunter.io/ios/topics/flow-wms) · [fire hydrant](https://appshunter.io/ios/topics/fire-hydrant) · [open channel flow pro](https://appshunter.io/ios/topics/open-channel-flow-pro) · [flow free alternative](https://appshunter.io/ios/topics/flow-free-alternative) · [water flow calculators](https://appshunter.io/ios/topics/water-flow-calculators) · [hydrant](https://appshunter.io/ios/topics/hydrant) · [flow production tracking](https://appshunter.io/ios/topics/flow-production-tracking) · [open flow pro](https://appshunter.io/ios/topics/open-flow-pro) · [flowering flow pro](https://appshunter.io/ios/topics/flowering-flow-pro) · [worksight flow](https://appshunter.io/ios/topics/worksight-flow) · [brilionxflow](https://appshunter.io/ios/topics/brilionxflow) · [whspr flow](https://appshunter.io/ios/topics/whspr-flow) · [flow rate calculator alternative](https://appshunter.io/ios/topics/flow-rate-calculator-alternative) · [sluice](https://appshunter.io/ios/topics/sluice) --- *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 2026-06-03.*