# PPI Calc vs Device System Services

The clearest difference is in-app purchases: PPI Calc at none against Device System Services's 1. PPI Calc also leads on ads (none vs shown) and review sentiment (71% vs 52%). Device System Services's advantage is ratings volume (394 vs 13). On price, rating and device support there is nothing between them.

Both are free to download. Device System Services sells 1 one-off in-app purchase. PPI Calc asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 4.4 for PPI Calc against 4.5 for Device System Services. That said, the two scores are not equally well evidenced: Device System Services has 394 ratings behind it against 13, so its average is the more settled of the two. Written reviews are what separate them: 71% of PPI Calc's written reviews are positive against 52% of Device System Services's.

## The numbers

| Metric | PPI Calc | Device System Services |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.4 (13 ratings)](https://appshunter.io/ios/app/ppi-calc-ppi-calculator/id898198587/reviews) | **[4.5 (394 ratings)](https://appshunter.io/ios/app/device-system-services-tools/id1126227676/reviews)** |
| Number of ratings | 13 | **394** |
| Positive reviews | **71.4% of reviews** | 52.3% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | — | Every 4 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 1 MB | 9 MB |
| Requires iOS | **7.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Fausto Ristagno](https://appshunter.io/developer/482102205) | [Albert Parti](https://appshunter.io/developer/534966701) |

## What reviewers say

### PPI Calc

[App page](https://appshunter.io/ios/app/ppi-calc-ppi-calculator/id898198587)

Calculate pixels per inch (PPI) for any screen, along with aspect ratio and screen measurements. View data in inches or centimeters. Includes presets for standard resolutions and common devices.

**Highlights:** PPI calculation, Aspect ratio display, Screen height and width, Screen area calculation, Inch and centimeter units, Standard resolution presets, Common device presets

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

**In-app purchases:** none


### Device System Services

[App page](https://appshunter.io/ios/app/device-system-services-tools/id1126227676)

Monitor your device's hardware, network, memory, and storage with detailed insights and performance tracking. Includes diagnostic tools for network analysis and storage management. Offers widgets for real-time system information.

**Highlights:** Hardware specifications, Network status and diagnostics, Memory usage monitoring, Ping, LAN Scan, Port Scan tools, Storage management, System information widgets

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove ads System Service | $1.99 | one-time |

**What reviewers like**

- 👍 Clean and easy-to-use interface
- 🚀 Fast and responsive performance
- 📊 Comprehensive system information display
- 🌐 Useful network information details
- ⏱️ Shows device uptime information

**What reviewers complain about**

- 📺 Excessive full-screen video advertisements
- 🔊 Intrusive ads with sound that startle users
- ⚠️ Misleading security/storage warning popups
- 🎮 Irrelevant ads (e.g., game ads on iOS)
- 💰 Ads present even in paid version

**Reported bugs**

- App crashes on startup/launch
- Crashes when network module acquires external IP
- Requires airplane mode or disabled connectivity to function
- Incorrect device specifications (resolution, model variants)
- Static pie charts instead of dynamic system statistics

**Requested features**

- Option to delete accidentally copied items
- System reset functionality to restore original settings
- Camera information display
- External USB disk space usage tracking
- Memory cleaning/optimization features


## Frequently asked questions

### Is PPI Calc free?

PPI Calc is free to download, with no in-app purchases.

### Is Device System Services free?

Device System Services is free to download, with in-app purchases available.

### Which has better reviews, PPI Calc or Device System Services?

Device System Services is rated higher. PPI Calc averages 4.4 out of 5 from 13 ratings, while Device System Services averages 4.5 from 394 ratings.

### Do PPI Calc or Device System Services have ads?

Device System Services shows ads; PPI Calc does not.

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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.*