# Weir Open Channel Flow Calc — Weir Flow Rate Calculator

> Weir Flow Rate Calculator (iPhone/iPad app by Shanghai Sheyuan Network Technology Co., Ltd..)

- Source: https://appshunter.io/ios/app/weir-open-channel-flow-calc/id6761743066 (this page in markdown: same URL + `.md`)
- Developer: [Shanghai Sheyuan Network Technology Co., Ltd.](https://appshunter.io/developer/1560626858)
- Category: Utilities
- Price: $1.99
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: English
- Released: 2026-04-08
- Data updated: 2026-07-09
- User reviews in markdown: https://appshunter.io/ios/app/weir-open-channel-flow-calc/id6761743066/reviews.md

## What is Weir Open Channel Flow Calc?

Need to measure open-channel flow at a weir and get results in CFS, GPM, or MGD without hauling out reference tables? Select V-Notch, Rectangular (Francis), or Cipolletti weir type, enter the head measurement, and get instant flow calculations in five unit systems.

Supports V-Notch (adjustable notch angle: 22.5, 30, 45, 60, 90, 120 degrees), Rectangular with end contractions (Francis formula), and Cipolletti trapezoidal weirs.

FLOW OUTPUT UNITS:
- CFS (cubic feet per second)
- GPM (gallons per minute)
- MGD (million gallons per day)
- m3/s (cubic meters per second)
- L/s (liters per second)

KEY FEATURES:
- Three weir types in one app
- Adjustable notch angle for V-Notch weirs
- End contraction settings for rectangular weirs
- Instant results as you type
- Works completely offline
- No account or login required

Essential for hydrology field work, stormwater monitoring, irrigation measurement, and water resources engineering.


## Version history (last 3 releases)

### 1.0.2 — 2026-07-01

Added a More Pro Tools section to discover related field calculators.

### 1.0.1 — 2026-04-12

Bug fixes and performance improvements.

### 1.0 — 2026-04-08

No release notes.

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All apps by Shanghai Sheyuan Network Technology Co., Ltd.: https://appshunter.io/developer/1560626858

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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 2026-07-09.*