# Linear Interpolation Master vs 4

The clearest difference is rating: Linear Interpolation Master at 4.7 against 4's 3.0. Linear Interpolation Master also leads on ratings volume (176 vs 2) and update cadence (every 5 months vs every 11 months). 4's advantage is in-app purchases (none vs 3) and ads (none vs shown). 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. 4 asks for nothing beyond the download.

Linear Interpolation Master holds the better App Store score, 4.7 against 3.0. That said, the two scores are not equally well evidenced: Linear Interpolation Master has 176 ratings behind it against 2, so its average is the more settled of the two.

Linear Interpolation Master ships an update every 5 months, 4 every 11 months. The most recent releases landed on September 22, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | Linear Interpolation Master | 4 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (176 ratings)](https://appshunter.io/ios/app/linear-interpolation-master/id1433976994/reviews)** | [3.0 (2 ratings)](https://appshunter.io/ios/app/4-20-temperature-calculator/id1602351736/reviews) |
| Number of ratings | **176** | 2 |
| Positive reviews | 62.5% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 5 months** | Every 11 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 16 MB | 30 MB |
| Requires iOS | **11.0** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [VERVE TECHNOLOGIES PTY. LTD.](https://appshunter.io/developer/582523354) | [Mantas Kamarauskas](https://appshunter.io/developer/975306268) |

## What reviewers say

### 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 |


### 4

[App page](https://appshunter.io/ios/app/4-20-temperature-calculator/id1602351736)

This utility app converts between 4-20 mA current signals and temperature readings. It's designed for engineers and technicians to quickly check transmitter scaling, verify loop values, and troubleshoot signal issues in various industrial applications.

**Highlights:** Two-way current to temperature conversion, Custom min/max process range, Support for negative temperatures, Celsius and Fahrenheit support, Fast and clean interface

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Linear Interpolation Master free?

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

### Is 4 free?

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

### Which has better reviews, Linear Interpolation Master or 4?

Linear Interpolation Master is rated higher. Linear Interpolation Master averages 4.7 out of 5 from 176 ratings, while 4 averages 3.0 from 2 ratings.

### Do Linear Interpolation Master or 4 have ads?

Linear Interpolation Master shows ads; 4 does not.

### Which is updated more often, Linear Interpolation Master or 4?

Linear Interpolation Master ships an update every 5 months, and 4 every 11 months. Most recently, Linear Interpolation Master was updated on September 22, 2026 and 4 on September 10, 2026.

---

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