# Flow Rate Help — Velocity + Diameter Calculator

> Liquid flow rate, pipe diameter, and velocity calculator with customizable units. (iPhone/iPad app by Armchair Engineering.)

- Source: https://appshunter.io/ios/app/flow-rate-help/id1009898806 (this page in markdown: same URL + `.md`)
- Developer: [Armchair Engineering](https://appshunter.io/developer/398901339)
- Category: Utilities, Productivity
- Price: $0.99
- Rating: 4.30/5 from 44 App Store ratings · 3 written reviews indexed
- Age rating: 4+
- Requires: iOS 11.0 · 3 MB
- Languages: American English
- Released: 2015-07-01
- Data updated: 2026-08-06
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/flow-rate-help/id1009898806/reviews.md

## What is Flow Rate Help?

Quickly find flow rate, required pipe diameter or velocity of a liquid!

Features Include: 

- Accurately solve flow rate equations
- Set preferred diameter unit from: mm, cm, m, km, inches, feet, yards and miles
- Set preferred velocity unit from: m/s, m/min, km/min, km/h, ft/s, ft/min, mi/min and mph
- Set preferred flow rate unit from: m³/s, m³/min, m³/h, l/s, l/min, l/h, gps. gpm and gph
- Select your preferred number of decimal places

## Key features

- Solve flow rate equations
- Customizable diameter units
- Customizable velocity units
- Customizable flow rate units
- Set decimal places

## Recent user reviews (3 of 3)

All indexed reviews: https://appshunter.io/ios/app/flow-rate-help/id1009898806/reviews.md

### 2/5 — Used to work great

*2020-06-18*

Not sure what’s going on but I can no longer type into the fields. Nothing shows up.

**Developer response:** Hi Romz000,
Sorry about that, this issue was caused by an oversight on my part in not handling iOS 13's dark mode properly. It should now be fixed.
Thanks for letting me know and kind regards,
David

### 1/5 — Does not compute

*2016-03-01*

Literally off by a factor of 10.  I can't believe I paid for this!!!!!

### 1/5 — Incorrect which kinda defeats the purpose

*2015-09-17*

Water traveling through a 6in pipe at 2.11 feet per second is not 2001gpm

## Frequently asked questions about Flow Rate Help

### What is Flow Rate Help?

Flow Rate Help is a utility app that allows users to quickly calculate the flow rate, required pipe diameter, or velocity of a liquid. It offers precise solutions for flow rate equations and supports a wide range of unit customizations.

### How much does Flow Rate Help cost?

Flow Rate Help is a paid application, priced at $0.99. This one-time purchase grants you access to all its features without any recurring fees.

### What units can I use with Flow Rate Help?

You can select preferred units for diameter (mm, cm, m, km, inches, feet, yards, miles), velocity (m/s, m/min, km/min, km/h, ft/s, ft/min, mi/min, mph), and flow rate (m³/s, m³/min, m³/h, l/s, l/min, l/h, gps, gpm, gph).

### Does Flow Rate Help have ads?

No, Flow Rate Help is ad-free. As a paid application, it provides an uninterrupted user experience without any advertisements.

### What devices is Flow Rate Help compatible with?

Flow Rate Help is compatible with Mac, iPhone, iPad, and iPod devices. This broad compatibility ensures you can use it across your Apple ecosystem.

### How often is Flow Rate Help updated?

The latest version of Flow Rate Help is 1.4, last updated on June 25, 2020. While updates have not been frequent recently, the app is stable and functional for its core purpose.

### What is the age rating for Flow Rate Help?

Flow Rate Help has an age rating of 4+. This indicates it is suitable for users of all ages, with no mature content.

### Can I choose the number of decimal places in Flow Rate Help?

Yes, Flow Rate Help allows you to select your preferred number of decimal places for calculations. This feature ensures the precision you need for your specific requirements.

## Version history (last 5 releases)

### 1.4 — 2020-06-25

- Dark mode improvements

### 1.3.1 — 2020-01-04

- Fixed floating keyboard bug, present on some devices running iOS 13
- iPad multitasking improvements

### 1.3 — 2018-02-02

- iPhone X support

### 1.2 — 2016-10-04

- Bug fixes (apologies to all that were given the wrong result in the previous version)
- iOS 10 support
- Updated icon

### 1.1 — 2015-07-16

- Initial iPad support

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All apps by Armchair Engineering: https://appshunter.io/developer/398901339

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*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 2026-08-06.*