# Do One Thing vs CaptiveAire Toolbox

The clearest difference is update cadence: Do One Thing at every 4 days against CaptiveAire Toolbox's weekly. Do One Thing also leads on device support (4 vs 2) and iOS requirement (13.0 vs 16.0). On price, ads and in-app purchases there is nothing between them.

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

Do One Thing ships an update every 4 days, CaptiveAire Toolbox weekly. The most recent releases landed on October 27, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Do One Thing | CaptiveAire Toolbox |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/captiveaire-toolbox/id6765656560/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 days** | Weekly |
| Monetization | — | Free |
| Size | 6 MB | 71 MB |
| Requires iOS | **13.0** | 16.0 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Zeyu Yin](https://appshunter.io/developer/1362976339) | [Captive-Aire Systems, Inc.](https://appshunter.io/developer/1896026735) |

## What reviewers say

### Do One Thing

[App page](https://appshunter.io/ios/app/do-one-thing-finger-diary/id1543636840)

**In-app purchases:** none


### CaptiveAire Toolbox

[App page](https://appshunter.io/ios/app/captiveaire-toolbox/id6765656560)

This app provides over 40 HVAC and building-systems engineering calculators. It's designed for field use, offering standard industry formulas for cooling, heating, ventilation, electrical sizing, and more. Access detailed formula definitions and reference data.

**Highlights:** 40+ HVAC engineering calculators, Cooling and heating load calculations, Ventilation and airflow tools, Electrical sizing and motor circuits, Duct and piping pressure drop, Reference data and psychrometric chart

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

**In-app purchases:** none


## Frequently asked questions

### Is Do One Thing free?

Do One Thing is free to download, with no in-app purchases.

### Is CaptiveAire Toolbox free?

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

### Do Do One Thing or CaptiveAire Toolbox have ads?

Neither Do One Thing nor CaptiveAire Toolbox shows ads.

### Which is updated more often, Do One Thing or CaptiveAire Toolbox?

Do One Thing ships an update every 4 days, and CaptiveAire Toolbox weekly. Most recently, Do One Thing was updated on October 27, 2026 and CaptiveAire Toolbox on October 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.*