# Units Free vs Marine Docker

The clearest difference is in-app purchases: Marine Docker at none against Units Free's 1. Units Free's advantage is iOS requirement (5.1.1 vs 13.4). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Units Free sells 1 one-off in-app purchase. Marine Docker asks for nothing beyond the download.

Units Free ships an update every 5 months, Marine Docker every 4 months. The most recent releases landed on October 24, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | Units Free | Marine Docker |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/units-free/id510615778/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 4 months** |
| Monetization | Free with in-app purchases | — |
| Size | 3 MB | 61 MB |
| Requires iOS | **5.1.1** | 13.4 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Piet Jonas](https://appshunter.io/developer/288060167) | [Kontis d.o.o.](https://appshunter.io/developer/1745258669) |

## What reviewers say

### Units Free

[App page](https://appshunter.io/ios/app/units-free/id510615778)

Easily convert between various units across multiple categories like length, temperature, and weight. Access past conversions through a history list and send calculations via email. This free version offers core functionality with an option to upgrade for full category access.

**Highlights:** Multiple unit categories (length, temp, weight, etc.), Metric and imperial system support, Conversion history list, Send calculations via email, iPad multitasking support

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Units Free Upgrade | $0.99 | one-time |


### Marine Docker

[App page](https://appshunter.io/ios/app/marine-docker/id6502378616)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Units Free free?

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

### Is Marine Docker free?

Marine Docker is free to download, with no in-app purchases.

### Do Units Free or Marine Docker have ads?

Neither Units Free nor Marine Docker shows ads.

### Which is updated more often, Units Free or Marine Docker?

Units Free ships an update every 5 months, and Marine Docker every 4 months. Most recently, Units Free was updated on October 24, 2026 and Marine Docker on September 10, 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.*