Model Scaler vs Ruler
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Model Scaler
This tool instantly converts measurements between U.S. Customary and Metric units for any modeling scale. It's designed to be fast, easy, and efficient for all types of scale modelers.
- Instant scale conversion
- U.S. Customary to Metric
- Metric to U.S. Customary
- Supports any modeling scale
- Fast and efficient
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Instant scale conversion tool for any modeling scale. Fast, easy and efficient scale model conversion. Quickly convert U.S. Customary and Metric measurements into any scale. Perfect for all scale modelers, railroad modelers and tabletop gamers.
Ruler
This app displays various measurement scales for length, including meters and inches. It allows users to set magnification ratios and reduced scales for different applications. Users can calibrate the ruler and adjust PPI settings for accurate measurements.
- 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
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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.
Screenshots
Verdict
The clearest difference is rating: Ruler at 3.7 against Model Scaler's 2.9. Ruler also leads on review sentiment (63% vs 40%). Model Scaler's advantage is in-app purchases (none vs 1) and ads (none vs shown). On price, update cadence and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Ruler sells 1 one-off in-app purchase. Model Scaler asks for nothing beyond the download.
Ruler holds the better App Store score, 3.7 against 2.9. Both are backed by a comparable volume of ratings — 12 and 3 respectively. Written reviews point the same way: 40% of Model Scaler's written reviews are positive against 63% of Ruler's.
Model Scaler ships an update every 6 months, Ruler every 5 months. The most recent releases landed on June 11, 2026 and June 1, 2026 respectively.
| Parameter | Model Scaler | Ruler |
|---|---|---|
| Price | Free | Free |
| Rating | 2.9 (12 ratings) | 3.7 (3 ratings) — better |
| Positive reviews | 40.0% of reviews | 63.0% of reviews — better |
| Number of ratings | 12 — better | 3 |
| Update frequency | Every 6 months | Every 5 months — better |
| Ads | No — better | Yes |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 9.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 11 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | Woodland Scenics | mitsunori oishi |
Customer experience
Model Scaler
Ruler
In-app purchases
Model Scaler
No in-app purchases
Ruler
- Hide Ads$0.99









