# NDX Ground Ops vs GTP API Gravity Calculator2

The clearest difference is price: NDX Ground Ops at Free against GTP API Gravity Calculator2's $9.99. NDX Ground Ops also leads on rating (5.0 vs 4.0). GTP API Gravity Calculator2's advantage is iOS requirement (12.0 vs 16.6). On ratings volume, update cadence, ads and in-app purchases there is nothing between them.

NDX Ground Ops is free to download; GTP API Gravity Calculator2 costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

NDX Ground Ops holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

NDX Ground Ops ships an update every 3 months, GTP API Gravity Calculator2 every 2 months. The most recent releases landed on October 9, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | NDX Ground Ops | GTP API Gravity Calculator2 |
| --- | --- | --- |
| Price | **Free** | $9.99 |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/ndx-ground-ops/id6504170678/reviews)** | [4.0 (1 ratings)](https://appshunter.io/ios/app/gtp-api-gravity-calculator2/id6742924006/reviews) |
| Number of ratings | **2** | 1 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 2 months** |
| Monetization | **Free** | Paid |
| Size | 19 MB | 9 MB |
| Requires iOS | 16.6 | **12.0** |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [NDX LLC](https://appshunter.io/developer/1720955127) | [Gammon Technical Products](https://appshunter.io/developer/1163782116) |

## What reviewers say

### NDX Ground Ops

[App page](https://appshunter.io/ios/app/ndx-ground-ops/id6504170678)

This application provides real-time aircraft tracking, allowing users to monitor movements, tows, and flights. It also enables the generation of reports and identification of damage, with detailed statistics available via a web interface.

**Highlights:** Real-time aircraft tracking, Movement and tow monitoring, Flight data display, Damage identification, Report generation, Web app statistics

**Features:** macOS Compatibility

**In-app purchases:** none


### GTP API Gravity Calculator2

[App page](https://appshunter.io/ios/app/gtp-api-gravity-calculator2/id6742924006)

This application calculates the corrected API gravity at 60°F for jet, gasoline, and diesel fuels. It also determines the total weight of the fuel. It's a digital replacement for physical slide calculators.

**Highlights:** Corrected API gravity calculation, Total fuel weight calculation, Supports jet, gasoline, and diesel fuels, Digital version of slide calculators, Developed in 2025

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

**In-app purchases:** none


## Frequently asked questions

### Is NDX Ground Ops free?

NDX Ground Ops is free to download, with no in-app purchases.

### Is GTP API Gravity Calculator2 free?

GTP API Gravity Calculator2 costs $9.99, with no in-app purchases.

### Which has better reviews, NDX Ground Ops or GTP API Gravity Calculator2?

NDX Ground Ops is rated higher. NDX Ground Ops averages 5.0 out of 5 from 2 ratings, while GTP API Gravity Calculator2 averages 4.0 from 1 ratings.

### Do NDX Ground Ops or GTP API Gravity Calculator2 have ads?

Neither NDX Ground Ops nor GTP API Gravity Calculator2 shows ads.

### Which is updated more often, NDX Ground Ops or GTP API Gravity Calculator2?

NDX Ground Ops ships an update every 3 months, and GTP API Gravity Calculator2 every 2 months. Most recently, NDX Ground Ops was updated on October 9, 2026 and GTP API Gravity Calculator2 on September 24, 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.*