# Chronometer vs Blue Light Filter

The clearest difference is price: Blue Light Filter at Free against Chronometer's $2.99. Blue Light Filter also leads on update cadence (weekly vs every 5 months) and ratings volume (137 vs 8). Chronometer's advantage is in-app purchases (none vs 5). On rating, review sentiment, ads and device support there is nothing between them.

Blue Light Filter is free to download; Chronometer costs $2.99 up front. Blue Light Filter sells 5 in-app purchases, starting at $4.99 per 7 days. Chronometer asks for nothing beyond the download.

Blue Light Filter holds the better App Store score, 3.3 against 3.1. That said, the two scores are not equally well evidenced: Blue Light Filter has 137 ratings behind it against 8, so its average is the more settled of the two. Written reviews point the same way: 0% of Chronometer's written reviews are positive against 3% of Blue Light Filter's.

Chronometer ships an update every 5 months, Blue Light Filter weekly. The most recent releases landed on October 8, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Chronometer | Blue Light Filter |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | [3.1 (8 ratings)](https://appshunter.io/ios/app/chronometer/id1562013733/reviews) | **[3.3 (137 ratings)](https://appshunter.io/ios/app/blue-light-filter/id6463748819/reviews)** |
| Number of ratings | 8 | **137** |
| Positive reviews | 0.0% of reviews | **2.6% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | **Weekly** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 3 MB | 19 MB |
| Requires iOS | 18.6 | **17.0** |
| Devices | iPhone, iPad | **iPhone, iPad, Mac** |
| Age rating | 4+ | 17+ |
| Developer | [Kilian Eisenegger](https://appshunter.io/developer/1333678887) | [Rivia Corp s.r.o.](https://appshunter.io/developer/1698333588) |

## What reviewers say

### Chronometer

[App page](https://appshunter.io/ios/app/chronometer/id1562013733)

Easily track your watch's accuracy against atomic time. Simply set your watch to atomic time, take a photo of the dial within the app, and record the difference. Analyze daily deviations over 15 days to assess your watch's performance.

**Highlights:** Track daily watch accuracy, Compare against atomic time, Photo capture for time reading, Altitude recording, Save data in CSV format, Analyze 15-day data trends

**In-app purchases:** none


### Blue Light Filter

[App page](https://appshunter.io/ios/app/blue-light-filter/id6463748819)

Reduce eye strain and improve sleep with an adjustable blue light filter. Organize your files, photos, and videos with an integrated file manager. Enjoy a seamless web browsing experience with built-in filtering and bookmarking.

**Highlights:** Adjustable blue light filter, Eye strain relief, Improved sleep quality, Intuitive file manager, Zip/unzip support, Integrated web browser

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly | $4.99 | per 7 days |
| 1 month | $6.99 | per month |
| Blue Light Filter - Monthly | $7.99 | per month |
| 1 year | $24.99 | per year |
| Annually | $29.99 | per year |


## Frequently asked questions

### Is Chronometer free?

Chronometer costs $2.99, with no in-app purchases.

### Is Blue Light Filter free?

Blue Light Filter is free to download, with in-app purchases available.

### Which has better reviews, Chronometer or Blue Light Filter?

Blue Light Filter is rated higher. Chronometer averages 3.1 out of 5 from 8 ratings, while Blue Light Filter averages 3.3 from 137 ratings.

### Do Chronometer or Blue Light Filter have ads?

Neither Chronometer nor Blue Light Filter shows ads.

### Which is updated more often, Chronometer or Blue Light Filter?

Chronometer ships an update every 5 months, and Blue Light Filter weekly. Most recently, Chronometer was updated on October 8, 2026 and Blue Light Filter on October 13, 2026.

---

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