# Ruler vs smart LK

The clearest difference is rating: smart LK at 5.0 against Ruler's 4.5. smart LK also leads on update cadence (monthly vs every 3 months). Ruler's advantage is ratings volume (4 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

smart LK holds the better App Store score, 5.0 against 4.5. Both are backed by a comparable volume of ratings — 4 and 1 respectively.

Ruler ships an update every 3 months, smart LK monthly. Both last shipped on November 3, 2026.

## The numbers

| Metric | Ruler | smart LK |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.5 (4 ratings)](https://appshunter.io/ios/app/ruler-a-simple-ar-ruler-app/id1287068680/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/smart-lk/id1492795311/reviews)** |
| Number of ratings | **4** | 1 |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free | Free |
| Size | 22 MB | 12 MB |
| Requires iOS | 11.0 | 11.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Play, Inc.](https://appshunter.io/developer/1078526009) | [libing yang](https://appshunter.io/developer/1435297539) |

## What reviewers say

### Ruler

[App page](https://appshunter.io/ios/app/ruler-a-simple-ar-ruler-app/id1287068680)

This utility app uses augmented reality to measure lengths and areas in the real world. Simply point your device's camera to get accurate measurements.

**Highlights:** Augmented reality measurement, Measure length, Measure area, Simple interface

**Features:** macOS Compatibility

**In-app purchases:** none


### smart LK

[App page](https://appshunter.io/ios/app/smart-lk/id1492795311)

Control your smart lock remotely with this app. It supports unlocking via password and offers security alerts for brute-force attempts on fingerprint locks, ensuring property safety.

**Highlights:** Remote unlocking, Password lock support, Brute force crack alerts, Property safety notifications

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Ruler free?

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

### Is smart LK free?

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

### Which has better reviews, Ruler or smart LK?

smart LK is rated higher. Ruler averages 4.5 out of 5 from 4 ratings, while smart LK averages 5.0 from 1 ratings.

### Do Ruler or smart LK have ads?

Neither Ruler nor smart LK shows ads.

### Which is updated more often, Ruler or smart LK?

Ruler ships an update every 3 months, and smart LK monthly. Most recently, Ruler was updated on November 3, 2026 and smart LK on November 3, 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.*