# Average ISA Deviation vs INSTGPS

The clearest difference is price: INSTGPS at Free against Average ISA Deviation's $3.99. INSTGPS also leads on iOS requirement (17.0 vs 26.1). On update cadence, ads, in-app purchases and device support there is nothing between them.

INSTGPS is free to download; Average ISA Deviation costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Average ISA Deviation ships an update every 14 months, INSTGPS every 10 months. The most recent releases landed on August 1, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Average ISA Deviation | INSTGPS |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[3.5 (2 ratings)](https://appshunter.io/ios/app/average-isa-deviation/id630933637/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 66.7% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 14 months | **Every 10 months** |
| Monetization | Paid | — |
| Size | 1 MB | 119 MB |
| Requires iOS | 26.1 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Juan Mauricio Padilla Villarreal](https://appshunter.io/developer/604279584) | [Daniel Roberto Barraza Cota](https://appshunter.io/developer/1535969568) |

## What reviewers say

### Average ISA Deviation

[App page](https://appshunter.io/ios/app/average-isa-deviation/id630933637)

This utility helps professional pilots quickly calculate average ISA temperature deviation for descent planning on specific aircraft models. It simplifies manual calculations, reduces workload, and operates offline, making it ideal for cockpit use.

**Highlights:** Calculate average ISA deviation, Reduce descent planning workload, Simplify manual calculations, Offline cockpit use, Designed by a pilot

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

**In-app purchases:** none


### INSTGPS

[App page](https://appshunter.io/ios/app/instgps/id1535969565)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Average ISA Deviation free?

Average ISA Deviation costs $3.99, with no in-app purchases.

### Is INSTGPS free?

INSTGPS is free to download, with no in-app purchases.

### Do Average ISA Deviation or INSTGPS have ads?

Neither Average ISA Deviation nor INSTGPS shows ads.

### Which is updated more often, Average ISA Deviation or INSTGPS?

Average ISA Deviation ships an update every 14 months, and INSTGPS every 10 months. Most recently, Average ISA Deviation was updated on August 1, 2026 and INSTGPS on September 7, 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.*