# Ultimate Slide Rule — user reviews

> 5 indexed App Store user reviews of Ultimate Slide Rule by Rowan Richards, rated 4.90/5 from 9 ratings.

- Source: https://appshunter.io/ios/app/ultimate-slide-rule/id6636523467/reviews
- App overview in markdown: https://appshunter.io/ios/app/ultimate-slide-rule/id6636523467.md
- Rating breakdown: 5★ 8 · 4★ 1 · 3★ 0 · 2★ 0 · 1★ 0

## Most critical reviews (5 lowest-rated)

### 4/5 — Index adjust

*2025-01-21*

Consider index tap adjust similar to the hairline home.  Love how the hairline centers with tap.

### 5/5 — Excellent usability

*2025-09-14*

This app implements a slide rule very well and its usability is excellent. Zoom and reversals are intuitive and pleasant to use.
The scale arrangement (especially the LL scales) are a bit unusual, but this is secondary to demonstrating the principles of the slide rule.

**Developer response:** Hi, Im glad you liked the slide rule. Im not much of an expert on the subject, so the scale layout was copied directly from a real slide rule I own. Sorry if it caused any confusion.

### 5/5 — Usable and educational

*2025-04-30*

It’s cleverly designed so you can actually use it from your phone. 

It includes integrated tutorials which actually teach you how to use a slide rule. 

Haven’t found any other SOS which do the same. Is great!

### 5/5 — Amazing App, Minuscule Error

*2024-12-19*

I loved the amazing functionality of this app. Virtually every calculation can be accomplished with the high accuracy and precision of the scales provided. However, I have noticed an error in the markings on the left side of LL2. Although the tick marks for 1.11 and 1.2 are placed correctly, the tick marks in between and the label of 1.15 are inaccurately placed. Other than this caveat, the slide rule is amazing as well as visually pleasing. The simple design with a well-thought-out color palette make the app pleasing to the eye. Additionally, the zooming and locate cursor functions make the app more accessible and ergonomic. I would highly recommend this app, but please fix the tick mark placement on LL2.

**Developer response:** Hello. Im glad you’re enjoying the app. I see what you’re referring to with the LL2 scale and I’ll try to fix it in the next update. Thanks for pointing it out.

### 5/5 — Best app ever

*2024-10-13*

This is a great app! Not a fault I can find. No ads! The rule is gorgeous and, unlike actual slide rules, very easy for me to see. You can even zoom in. 
My son is getting married today and I was trying to figure out last night during set-up if we had enough places sat for guests expected. I opened up the calculator app on my phone then thought “wait! I’ll use my slide rule app!”

---

*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 2026-09-06.*