# Orifice Flow vs Holtek MCU Selector

The clearest difference is price: Holtek MCU Selector at Free against Orifice Flow's $3.99. Holtek MCU Selector also leads on update cadence (every 2 months vs every 12 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Holtek MCU Selector is free to download; Orifice Flow costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Orifice Flow ships an update every 12 months, Holtek MCU Selector every 2 months. The most recent releases landed on October 11, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Orifice Flow | Holtek MCU Selector |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[4.0 (1 ratings)](https://appshunter.io/ios/app/orifice-flow/id479581349/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 2 months** |
| Monetization | Paid | — |
| Size | 1 MB | 19 MB |
| Requires iOS | 14.3 | **13.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Kaup Shenoy Associates](https://appshunter.io/developer/460148822) | [Holtek Semiconductor(China) Inc](https://appshunter.io/developer/1052056181) |

## What reviewers say

### Orifice Flow

[App page](https://appshunter.io/ios/app/orifice-flow/id479581349)

Calculate fluid flow rates in pipes and conduits using orifice plates. Supports common industrial fluids and custom fluid properties, with adjustable units and orifice types. Ideal for engineers and designers.

**Highlights:** Fluid flow rate computation, Supports 15 common industrial fluids, Custom fluid property input and saving, Multiple orifice plate types, Adjustable units (SI/USCS), Detailed computation model documentation

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Holtek MCU Selector

[App page](https://appshunter.io/ios/app/holtek-mcu-selector/id6444018542)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Orifice Flow free?

Orifice Flow costs $3.99, with no in-app purchases.

### Is Holtek MCU Selector free?

Holtek MCU Selector is free to download, with no in-app purchases.

### Do Orifice Flow or Holtek MCU Selector have ads?

Neither Orifice Flow nor Holtek MCU Selector shows ads.

### Which is updated more often, Orifice Flow or Holtek MCU Selector?

Orifice Flow ships an update every 12 months, and Holtek MCU Selector every 2 months. Most recently, Orifice Flow was updated on October 11, 2026 and Holtek MCU Selector on October 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*