# Drillstring Toolbox vs Gas Compressibility Factor Z

The clearest difference is update cadence: Gas Compressibility Factor Z at every 8 months against Drillstring Toolbox's every 39 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Drillstring Toolbox ships an update every 39 months, Gas Compressibility Factor Z every 8 months. Both last shipped on October 7, 2026.

## The numbers

| Metric | Drillstring Toolbox | Gas Compressibility Factor Z |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.3 (3 ratings)](https://appshunter.io/ios/app/drillstring-toolbox/id1068605189/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 39 months | **Every 8 months** |
| Monetization | Free | — |
| Size | 1 MB | 3 MB |
| Requires iOS | 14.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Bureau Veritas North America, Inc.](https://appshunter.io/developer/1770295442) | [Carlos Moura](https://appshunter.io/developer/407501202) |

## What reviewers say

### Drillstring Toolbox

[App page](https://appshunter.io/ios/app/drillstring-toolbox/id1068605189)

This utility app calculates drill-stem load capacities based on API connections and sizes. It also provides makeup torque and tensile capacity, as well as tensile and torsion capacities for drill pipe tubes.

**Highlights:** Drill-stem load capacity calculation, API connection selection, Makeup torque calculation, Tensile capacity calculation, Drill pipe tube capacities

**Features:** macOS Compatibility

**In-app purchases:** none


### Gas Compressibility Factor Z

[App page](https://appshunter.io/ios/app/gas-compressibility-factor-z/id1626924678)

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

**In-app purchases:** none


## Frequently asked questions

### Is Drillstring Toolbox free?

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

### Is Gas Compressibility Factor Z free?

Gas Compressibility Factor Z is free to download, with no in-app purchases.

### Do Drillstring Toolbox or Gas Compressibility Factor Z have ads?

Neither Drillstring Toolbox nor Gas Compressibility Factor Z shows ads.

### Which is updated more often, Drillstring Toolbox or Gas Compressibility Factor Z?

Drillstring Toolbox ships an update every 39 months, and Gas Compressibility Factor Z every 8 months. Most recently, Drillstring Toolbox was updated on October 7, 2026 and Gas Compressibility Factor Z on October 7, 2026.

---

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