# TallyRig vs HydroTech Pocket Engineer

The clearest difference is in-app purchases: HydroTech Pocket Engineer at none against TallyRig's 1. HydroTech Pocket Engineer also leads on update cadence (monthly vs every 3 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. TallyRig sells 1 one-off in-app purchase. HydroTech Pocket Engineer asks for nothing beyond the download.

TallyRig ships an update every 3 months, HydroTech Pocket Engineer monthly. The most recent releases landed on October 31, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | TallyRig | HydroTech Pocket Engineer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.0 (1 ratings)](https://appshunter.io/ios/app/tallyrig-well-control-calc/id6758645641/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free | — |
| Size | 33 MB | 3 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [嘉炜 丰](https://appshunter.io/developer/1759511819) | [michael schricker](https://appshunter.io/developer/1895753612) |

## What reviewers say

### TallyRig

[App page](https://appshunter.io/ios/app/tallyrig-well-control-calc/id6758645641)

This app provides a suite of 17 oilfield and drilling calculators designed for field use. It features a digital tally-book history to save and share results, with offline functionality and a user-friendly interface for rig environments. Supports multiple languages and unit systems.

**Highlights:** 17 oilfield & drilling calculators, Digital tally-book history, Offline-first functionality, Sunlight Mode for outdoor readability, Glove-friendly interface, Formula review and show-work, Imperial and Metric unit support

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| TallyRig Pro | $14.99 | one-time |


### HydroTech Pocket Engineer

[App page](https://appshunter.io/ios/app/hydrotech-pocket-engineer/id6764373443)

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

**In-app purchases:** none


## Frequently asked questions

### Is TallyRig free?

TallyRig is free to download, with in-app purchases available.

### Is HydroTech Pocket Engineer free?

HydroTech Pocket Engineer is free to download, with no in-app purchases.

### Do TallyRig or HydroTech Pocket Engineer have ads?

Neither TallyRig nor HydroTech Pocket Engineer shows ads.

### Which is updated more often, TallyRig or HydroTech Pocket Engineer?

TallyRig ships an update every 3 months, and HydroTech Pocket Engineer monthly. Most recently, TallyRig was updated on October 31, 2026 and HydroTech Pocket Engineer on October 28, 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.*