# Four To Twenty: mA/V Converter — user reviews

> 10 indexed App Store user reviews of Four To Twenty by Jon Giambattista, rated 4.50/5 from 10 ratings.

- Source: https://appshunter.io/ios/app/four-to-twenty-mav-converter/id1302909664/reviews
- App overview in markdown: https://appshunter.io/ios/app/four-to-twenty-mav-converter/id1302909664.md
- Rating breakdown: 5★ 7 · 4★ 2 · 3★ 0 · 2★ 1 · 1★ 0

## Most critical reviews (10 lowest-rated)

### 2/5 — Doesn’t support negative numbers

*2019-05-24*

Doesn’t support negative numbers for differential measurement

**Developer response:** Thanks for your review. An update will be coming shortly to fix this

### 2/5 — Ausbaufähig

*2019-05-20*

Bei der Eingabe der Werte wird nur ein Komma angezeigt, die App verarbeitet aber nur einen Punkt. Mit Umweg kann man dann seine Werte eingeben.

### 3/5 — Decent app but lacking functionality.

*2024-04-23*

This app is cool but I’m a little confused what the point of the changeable units is. Seems like a “feature” for the sake of having one. 

A feature that is needed is the ability to compute values outside of the set range. For example, converting a 3.5mA value to counts on a 4-20mA scale. A lot of troubleshooting involves out of range values.

### 3/5 — Decent product, needs a little work

*2018-10-31*

Works good as a signal calculator, but need to be able to use negative values for process variables, especially on temperature.

**Developer response:** Thanks for the feedback. I'll try to push an update soon that addresses this.

### 4/5 — Sehr nützlich,

*2022-10-18*

eine Erweiterung auf 3 Bereiche wäre noch besser. Auch farbige Schieberegler statt einfache Balkenanzeigen wären toll.

### 4/5 — Simple and easy

*2020-12-28*

I think it would be helpful if you added the math formula with it.

**Developer response:** Will look at adding the formula in the next update. Thanks for the feedback

### 5/5 — Very useful

*2025-04-02*

App is very useful but seems to be forgotten about as far new features being added. As another review stated a percentage would be super useful and to be able to rename the custom selection too.

### 5/5 — Great App!

*2022-11-12*

This app is fantastic!
Wonder what your thoughts are on adding what the 0-100% value would be.
Ex: 0-100•c 16mA would be 75%. This example is very easy but say we’re looking for 42% of the range. Hope this makes sense.

### 5/5 — Works well

*2021-04-16*

Quick and easy. It considers all the process variables units. Looks hot. Makes my job so much quicker. Rad.

**Developer response:** Thanks for the review!

### 5/5 — Works for work

*2017-12-07*

Simple and non cluttered interface makes it easy to use.  Great for old school analog devices that are adjusted by a POT.  Especially if adjustments have to be made with the transmitter in operation and you need to avoid going to minimum or maximum values. 

Not necessary but would like to see m3 for level as a units option.

**Developer response:** Thanks for the feedback. I'll add m3/level units in the next version.

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-25.*