# CrowdMag vs Linear Interpolation Master

The clearest difference is in-app purchases: CrowdMag at none against Linear Interpolation Master's 3. CrowdMag also leads on ads (none vs shown) and update cadence (every 2 months vs every 5 months). Linear Interpolation Master's advantage is rating (4.7 vs 4.3) and ratings volume (176 vs 24). On price and device support there is nothing between them.

Both are free to download. Linear Interpolation Master sells 3 one-off in-app purchases. CrowdMag asks for nothing beyond the download.

Linear Interpolation Master holds the better App Store score, 4.7 against 4.3. That said, the two scores are not equally well evidenced: Linear Interpolation Master has 176 ratings behind it against 24, so its average is the more settled of the two. Written reviews point the same way: 53% of CrowdMag's written reviews are positive against 63% of Linear Interpolation Master's.

CrowdMag ships an update every 2 months, Linear Interpolation Master every 5 months. Both last shipped on September 22, 2026.

## The numbers

| Metric | CrowdMag | Linear Interpolation Master |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.3 (24 ratings)](https://appshunter.io/ios/app/crowdmag/id910578825/reviews) | **[4.7 (176 ratings)](https://appshunter.io/ios/app/linear-interpolation-master/id1433976994/reviews)** |
| Number of ratings | 24 | **176** |
| Positive reviews | 52.9% of reviews | **62.5% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 2 months** | Every 5 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 18 MB | 16 MB |
| Requires iOS | 15.0 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [University of Colorado Boulder](https://appshunter.io/developer/972210292) | [VERVE TECHNOLOGIES PTY. LTD.](https://appshunter.io/developer/582523354) |

## What reviewers say

### CrowdMag

[App page](https://appshunter.io/ios/app/crowdmag/id910578825)

This app allows users to measure and contribute to scientific research on Earth's magnetic field using their smartphone. It offers features for recording magnetic data during various activities, including flights, and provides tools for data visualization and analysis.

**Highlights:** Measure magnetic field data, Contribute to scientific research, Record data during flights, Visualize data on maps and graphs, Magnetic calculator with WMM2020, Live magnetic compass, Export data via email/Google Drive

**Features:** macOS Compatibility

**In-app purchases:** none


### Linear Interpolation Master

[App page](https://appshunter.io/ios/app/linear-interpolation-master/id1433976994)

This tool simplifies linear interpolation calculations for industrial commissioning engineers. It features large, easily readable numbers for field use and allows for quick swapping of coordinate systems, such as converting between 4-20mA and 0-100% scales.

**Highlights:** Large number display for field visibility, Quickly swap X and Y coordinates, 4-20mA to 0-100% conversion, 0-100% to 4-20mA conversion

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Generous Tip | $2.99 | one-time |
| Massive Tip | $3.99 | one-time |
| Amazing Tip | $4.99 | one-time |


## Frequently asked questions

### Is CrowdMag free?

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

### Is Linear Interpolation Master free?

Linear Interpolation Master is free to download, with in-app purchases available.

### Which has better reviews, CrowdMag or Linear Interpolation Master?

Linear Interpolation Master is rated higher. CrowdMag averages 4.3 out of 5 from 24 ratings, while Linear Interpolation Master averages 4.7 from 176 ratings.

### Do CrowdMag or Linear Interpolation Master have ads?

Linear Interpolation Master shows ads; CrowdMag does not.

### Which is updated more often, CrowdMag or Linear Interpolation Master?

CrowdMag ships an update every 2 months, and Linear Interpolation Master every 5 months. Most recently, CrowdMag was updated on September 22, 2026 and Linear Interpolation Master on September 22, 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.*