# Viscosity Conversion vs Orifice Flow Rate Calculator

The clearest difference is price: Orifice Flow Rate Calculator at Free against Viscosity Conversion's $2.99. Orifice Flow Rate Calculator also leads on update cadence (every 6 months vs every 30 months). Viscosity Conversion's advantage is iOS requirement (13 vs 15.6). On ads, in-app purchases and device support there is nothing between them.

Orifice Flow Rate Calculator is free to download; Viscosity Conversion costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Viscosity Conversion ships an update every 30 months, Orifice Flow Rate Calculator every 6 months. Both last shipped on October 9, 2026.

## The numbers

| Metric | Viscosity Conversion | Orifice Flow Rate Calculator |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | — | **[4.9 (98 ratings)](https://appshunter.io/ios/app/orifice-flow-rate-calculator/id1439701941/reviews)** |
| Number of ratings | — | **98** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 30 months | **Every 6 months** |
| Monetization | — | Free |
| Size | 1 MB | 2 MB |
| Requires iOS | **13** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [R.L. Laughlin & Company, Inc.](https://appshunter.io/developer/1438670681) |

## What reviewers say

### Viscosity Conversion

[App page](https://appshunter.io/ios/app/viscosity-conversion/id630288155)

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

**In-app purchases:** none


### Orifice Flow Rate Calculator

[App page](https://appshunter.io/ios/app/orifice-flow-rate-calculator/id1439701941)

Easily calculate natural gas orifice flow rates using the AGA 3 standard. This utility app allows users to determine MCF production for a given duration, save calculations, and export data to CSV. It functions offline, requiring no cell service.

**Highlights:** Orifice MCF Calculator, Rotary (Direct) MCF Calculator, Save all calculations, View saved inputs and calculations, Export calculations to CSV

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Viscosity Conversion free?

Viscosity Conversion costs $2.99, with no in-app purchases.

### Is Orifice Flow Rate Calculator free?

Orifice Flow Rate Calculator is free to download, with no in-app purchases.

### Do Viscosity Conversion or Orifice Flow Rate Calculator have ads?

Neither Viscosity Conversion nor Orifice Flow Rate Calculator shows ads.

### Which is updated more often, Viscosity Conversion or Orifice Flow Rate Calculator?

Viscosity Conversion ships an update every 30 months, and Orifice Flow Rate Calculator every 6 months. Most recently, Viscosity Conversion was updated on October 9, 2026 and Orifice Flow Rate Calculator on October 9, 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.*