# HydroTech Pocket Engineer vs Screw Size Drill Bit Chart

The clearest difference is in-app purchases: HydroTech Pocket Engineer at none against Screw Size Drill Bit Chart's 3. HydroTech Pocket Engineer also leads on device support (3 vs 1) and iOS requirement (15.0 vs 17.0). On price, update cadence and ads there is nothing between them.

Both are free to download. Screw Size Drill Bit Chart sells 3 in-app purchases, starting at $2.99 per 7 days. HydroTech Pocket Engineer asks for nothing beyond the download.

Both ship on a similar rhythm, roughly monthly. The most recent releases landed on October 1, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | HydroTech Pocket Engineer | Screw Size Drill Bit Chart |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Monthly | Monthly |
| Size | 3 MB | 23 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 17+ | 4+ |
| Developer | [michael schricker](https://appshunter.io/developer/1895753612) | [Phuc Pham](https://appshunter.io/developer/1893081423) |

## What reviewers say

### HydroTech Pocket Engineer

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

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

**In-app purchases:** none


### Screw Size Drill Bit Chart

[App page](https://appshunter.io/ios/app/screw-size-drill-bit-chart/id6772276125)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Countersink Pro, Weekly | $2.99 | per 7 days |
| Thread Finder, Yearly | $14.99 | per year |
| Full Fastener Guide, One-Time | $29.99 | one-time |


## Frequently asked questions

### Is HydroTech Pocket Engineer free?

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

### Is Screw Size Drill Bit Chart free?

Screw Size Drill Bit Chart is free to download, with in-app purchases available.

### Do HydroTech Pocket Engineer or Screw Size Drill Bit Chart have ads?

Neither HydroTech Pocket Engineer nor Screw Size Drill Bit Chart shows ads.

### Which is updated more often, HydroTech Pocket Engineer or Screw Size Drill Bit Chart?

HydroTech Pocket Engineer ships an update monthly, and Screw Size Drill Bit Chart monthly. Most recently, HydroTech Pocket Engineer was updated on October 1, 2026 and Screw Size Drill Bit Chart on October 6, 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.*