# Ruler - Scale Ruler — Various scales can be set!

> App for displaying and setting various measurement scales and units. (iPhone/iPad app by mitsunori oishi.)

- Source: https://appshunter.io/ios/app/ruler-scale-ruler/id919130707 (this page in markdown: same URL + `.md`)
- Developer: [mitsunori oishi](https://appshunter.io/developer/905649994)
- Category: Productivity, Utilities
- Price: Free with in-app purchases
- Rating: 3.67/5 from 3 App Store ratings · 27 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.0 · 4 MB
- Languages: English, Japanese
- Released: 2014-10-08
- Data updated: 2026-06-01
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/ruler-scale-ruler/id919130707/reviews.md

## What is Ruler?

Scale Ruler is the simple application to display the scale of various measurement units.
※ Warning:
- The accuracy of the scales cannot be guaranteed.
- Calibration and PPI values ​​will be reset when the model changes.
- Set the PPI value only when the model is undecided.
- When you change the PPI value, perform calibration after the change.


■How to use:

■Select mode
In UNLOCKED state, after choosing measurement unit, magnification ratio and reduced scale, the scale is displayed.

■Free mode
When dragging the screen at UNLOCK, you can set the scale in the range 1: 1 to 1: 100.
When you press and hold the scale value, the keyboard is displayed and you can enter the scale.

You can lock the scale on the ruler with a switch.
Sorry for the advertisement during unlocking.
After In-App Purchase, your ads will no longer be displayed.

Specification of Scale Ruler
- measure length
   meter,inches

- magnification ratio
   50% , 70.7% , 100% , 141% , 200%

- reduced scale
　for meter　
　　1:100 , 1:150 , 1:200 , 1:250  , 1:300 , 1:400 , 1:500 , 1:600

　for inch
　　1:1 , 1:1.5 , 1:2 , 1:2.5  , 1:3 , 1:4 , 1:5 , 1:6

　for inch(Architectural)
　　1:1 , 1:2 , 1:4 , 1:8  , 1:12 , 1:16 , 1:24 , 1:32 , 1:48 , 1:64
　　1:96 , 1:128 , 1:192 , 1:384

　for inch(Engineering)
       1:120 , 1:240 , 1:360 , 1:480  , 1:600 , 1:720
       1:800 , 1:960 , 1:1080

■ Settings
- Calibration
- PPI (pixels per inch) setting
- In-app purchase (ads not displayed)
- In-app purchase restoration


■ Calibration
Adjust the length of the ruler.
Use the correct ruler for adjustment.

"Calibration" button: Records the adjusted state and reflects the calibration result on the ruler.
"Reset" button: Returns the adjustment status to the specified value. It will not be recorded.
"Initialize" button: Returns the adjustment status to the specified value and reflects it on the ruler.
* Caution: The calibration value will be reset when the model changes.

■ PPI (pixels per inch) setting
If the model is undecided, check the PPI value of the model before setting the PPI value.
* Please set only when the model is undecided.

"OK" button: Record the entered PPI value and reflect it on the ruler display.
"Initialize" button: Returns the PPI value to the specified value and reflects it on the ruler.
* Caution: The PPI value will be reset when the model changes.

## Key features

- Display various measurement scales
- Set magnification ratios
- Set reduced scales
- Measure in meters and inches
- Free mode for custom scales
- Calibration for accuracy
- PPI setting

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Hide Ads | $0.99 | one-time |


## Recent user reviews (10 of 27)

All indexed reviews: https://appshunter.io/ios/app/ruler-scale-ruler/id919130707/reviews.md

### 5/5 — 凄く良い

*2025-11-08, version 4.6*

さんすけを持ち歩く必要が無く、どんな縮尺にも任意に対応できるのは凄くありがたい！

アプリ起動時に1回目は基本的にフリーズ、アプリを再起動すると動き始めるので、何か不具合があると予想。修正されたら、よりありがたいです。

### 5/5 — Works properly!

*2022-12-25, version 4.2*

Using iPhone 13 Pro Max, works great!

### 5/5 — 不具合即対応

*2020-11-18, version 3.10*

チョイルーラーにやっぱり便利

### 1/5 — 何で

*2020-02-26, version 3.8.1*

アプリが全く立ち上がらない。
アイコンタップしたらホーム画面に戻るだけ。

### 4/5 — 要望

*2020-01-05, version 3.8.1*

iPhone7ですが、かなりいい精度です
キャリブレーション機能と、画面の回転に対応していただけるとより便利だと思います

### 5/5 — Very useful

*2019-04-19, version 3.5*

Good

### 4/5 — インチが

*2018-11-20, version 3.5*

ちょっと短いようにも思うのですが、手元のインドネシア製定規のほうがちょっと長いのかも。iPad Pro 11インチです。

### 5/5 — É precisa

*2018-07-29, version 3.3*

No meu iPhone 5S marcou precisamente

### 1/5 — 本物の定規とあわない

*2018-05-10, version 3.3*

iPhone6sで使用。画面の上に定規を乗せてあってるか確認したがあわない。少し大きい。残念

### 1/5 — not working

*2018-01-06*

not working, instantly closing

## Frequently asked questions about Ruler

### What does the Ruler - Scale Ruler app do?

The app displays various measurement scales for length, allowing users to set magnification ratios and reduced scales. It supports measurement in meters and inches, and offers a free mode for custom scale settings. Users can also calibrate the ruler and adjust PPI settings for improved accuracy.

### What are the key features of this ruler app?

Key features include the ability to display various measurement scales, set magnification ratios (e.g., 50%, 100%, 200%), and set reduced scales for meters and inches. It also offers a free mode for custom scale input, calibration to adjust ruler length, and PPI settings.

### How much does the Ruler - Scale Ruler app cost?

The app is free to download and use, but it displays advertisements during unlocking. Users can make an in-app purchase to remove these advertisements. There is also an option to restore in-app purchases.

### Can I calibrate the ruler for more accurate measurements?

Yes, the app includes a calibration feature. You can adjust the length of the ruler using a correct ruler for reference. The 'Calibration' button records the adjusted state, while 'Reset' and 'Initialize' buttons allow for returning to specified or initial values.

### What are the different scale options available?

The app offers a wide range of reduced scales for meters (e.g., 1:100, 1:500) and inches, including architectural (e.g., 1:4, 1:64) and engineering (e.g., 1:120, 1:960) scales. Magnification ratios like 50%, 100%, and 200% are also available.

## Version history (last 5 releases)

### 4.7 — 2026-03-19

Update for iPhone17e ,iPad Air 11-inch(M4),iPad Air 13-inch(M4).

### 4.6 — 2025-10-17

Update for iPhoneAir ,iPhone17 ,iPhone 17 Pro ,iPhone 17 Pro Max.

### 4.5 — 2025-03-11

Update for iPhone 16e  , iPad(10.9-inch)(A16)  , iPad Air 11-inch (M3) , iPad Air 13-inch (M3) .

### 4.4 — 2024-09-21

Update for iPhone 16 , iPhone 16 Plus , iPhone 16 Pro , iPhone 16 Pro Max , iPad Pro(12.9-inch)(6rd generation)  , iPad Air4(10.9-inch)(M2) , iPad Air4(12.9-inch)(M2) , iPad Pro(11-inch)(M4) ,  iPad Pro(13-inch)(M4) .

### 4.3 — 2023-09-27

Update for iPhone 15 , iPhone 15 Plus , iPhone 15 Pro , iPhone 15 Pro Max.

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## More apps by mitsunori oishi

- [語呂合わせ電卓](https://appshunter.io/ios/app/id905649991)
- [MapRuler for paper map](https://appshunter.io/ios/app/mapruler-for-paper-map/id949274313)
- [Bolt Length - (Nominal Length)](https://appshunter.io/ios/app/bolt-length-nominal-length/id1042345193)
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- [Ring Sizer for Japan](https://appshunter.io/ios/app/ring-sizer-for-japan/id1090995858)

All apps by mitsunori oishi: https://appshunter.io/developer/905649994

## Related topics

[scaler 3](https://appshunter.io/ios/topics/scaler-3) · [scale calculator](https://appshunter.io/ios/topics/scale-calculator) · [scale up](https://appshunter.io/ios/topics/scale-up) · [lark scale](https://appshunter.io/ios/topics/lark-scale)

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*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 2026-06-01.*