# Blue Def Decoder vs Fuel Log

The clearest difference is price: Fuel Log at Free against Blue Def Decoder's $3.99. Blue Def Decoder's advantage is iOS requirement (15.1 vs 17.0). On update cadence, ads, in-app purchases and device support there is nothing between them.

Fuel Log is free to download; Blue Def Decoder costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Blue Def Decoder ships an update every 5 months, Fuel Log every 4 months. The most recent releases landed on October 9, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Blue Def Decoder | Fuel Log |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[3.0 (6 ratings)](https://appshunter.io/ios/app/blue-def-decoder/id6751862301/reviews)** | — |
| Number of ratings | **6** | — |
| Positive reviews | 60.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 4 months** |
| Monetization | Paid | — |
| Size | 20 MB | 4 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Mako Technology Labs](https://appshunter.io/developer/1832176903) | [LEAN ASIA CO., LTD](https://appshunter.io/developer/1815050814) |

## What reviewers say

### Blue Def Decoder

[App page](https://appshunter.io/ios/app/blue-def-decoder/id6751862301)

Instantly determine the freshness of your Diesel Exhaust Fluid (DEF) by entering the code from your container. This app helps you confirm DEF hasn't expired, track shelf life, and verify vehicle compliance, removing guesswork for diesel vehicle owners.

**Highlights:** Check DEF freshness, Enter 5-11 character codes, View manufacturing date, See freshness status, Track shelf life, Verify vehicle compliance

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

**In-app purchases:** none


### Fuel Log

[App page](https://appshunter.io/ios/app/fuel-log-gas-mpg-tracker/id6772262900)

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

**In-app purchases:** none


## Frequently asked questions

### Is Blue Def Decoder free?

Blue Def Decoder costs $3.99, with no in-app purchases.

### Is Fuel Log free?

Fuel Log is free to download, with no in-app purchases.

### Do Blue Def Decoder or Fuel Log have ads?

Neither Blue Def Decoder nor Fuel Log shows ads.

### Which is updated more often, Blue Def Decoder or Fuel Log?

Blue Def Decoder ships an update every 5 months, and Fuel Log every 4 months. Most recently, Blue Def Decoder was updated on October 9, 2026 and Fuel Log on October 13, 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.*