# Julianator vs Blue Def Decoder

The clearest difference is rating: Julianator at 4.7 against Blue Def Decoder's 3.0. Julianator also leads on ratings volume (117 vs 6) and price ($0.99 vs $3.99). Blue Def Decoder's advantage is iOS requirement (15.1 vs 17.4). On update cadence, ads, in-app purchases and chart position there is nothing between them.

Julianator costs $0.99 and Blue Def Decoder $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Julianator holds the better App Store score, 4.7 against 3.0. That said, the two scores are not equally well evidenced: Julianator has 117 ratings behind it against 6, so its average is the more settled of the two. Written reviews point the same way: 70% of Julianator's written reviews are positive against 60% of Blue Def Decoder's.

Julianator ships an update every 3 months, Blue Def Decoder every 5 months. The most recent releases landed on October 10, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | Julianator | Blue Def Decoder |
| --- | --- | --- |
| Price | **$0.99** | $3.99 |
| Rating | **[4.7 (117 ratings)](https://appshunter.io/ios/app/julianator/id383950353/reviews)** | [3.0 (6 ratings)](https://appshunter.io/ios/app/blue-def-decoder/id6751862301/reviews) |
| Number of ratings | **117** | 6 |
| Positive reviews | **70.4% of reviews** | 60.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 5 months |
| Monetization | **Free** | Paid |
| Best chart rank | #183 | **#168** |
| Size | 4 MB | 20 MB |
| Requires iOS | 17.4 | **15.1** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Bright Day Digital LLC](https://appshunter.io/developer/383950356) | [Mako Technology Labs](https://appshunter.io/developer/1832176903) |

## What reviewers say

### Julianator

[App page](https://appshunter.io/ios/app/julianator/id383950353)

**Currently charting:** #183 Top Paid · Utilities (US App Store)

Easily convert dates between the Gregorian calendar and the Julian Day of Year (ordinal date). This tool is useful for systems that use day-of-year numbering, such as mainframes, military, and food industries. It offers a clean interface, monthly views, and widgets for quick access.

**Highlights:** Gregorian to Julian Day of Year conversion, Julian Day of Year to Gregorian conversion, Monthly calendar view, Home Screen widgets, Lock Screen widgets, Watch app with complications

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


### Blue Def Decoder

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

**Currently charting:** #168 Top Paid · Utilities (US App Store)

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


## Frequently asked questions

### Is Julianator free?

Julianator costs $0.99, with no in-app purchases.

### Is Blue Def Decoder free?

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

### Which has better reviews, Julianator or Blue Def Decoder?

Julianator is rated higher. Julianator averages 4.7 out of 5 from 117 ratings, while Blue Def Decoder averages 3.0 from 6 ratings.

### Do Julianator or Blue Def Decoder have ads?

Neither Julianator nor Blue Def Decoder shows ads.

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

Julianator ships an update every 3 months, and Blue Def Decoder every 5 months. Most recently, Julianator was updated on October 10, 2026 and Blue Def Decoder on October 9, 2026.

### Which is more popular, Julianator or Blue Def Decoder?

Julianator currently peaks at #183 in the App Store charts, and Blue Def Decoder at #168. Chart position reflects recent download velocity rather than total install base.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*