Comparison

Model Scaler vs Ruler

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • Instant scale conversion
  • U.S. Customary to Metric
  • Metric to U.S. Customary
  • Supports any modeling scale
  • Fast and efficient
Features
Read full description

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.

About

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.

Highlights
  • 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
Features
Read full description

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

Model Scaler1 screens
Ruler4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Ruler sells 1 one-off in-app purchase. Model Scaler asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard7 real differences · 3 level
Model Scaler versus Ruler: the parameters behind the verdict, then further details
ParameterModel ScalerRuler
PriceFreeFree
Rating2.9 (12 ratings)3.7 (3 ratings) — better
Positive reviews40.0% of reviews63.0% of reviews — better
Number of ratings12 — better3
Update frequencyEvery 6 monthsEvery 5 months — better
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS9.0 — better15.0
Further details — not scored
Size11 MB4 MB
Age rating4+4+
DeveloperWoodland Scenicsmitsunori oishi

Customer experience

Model Scaler

All ratings12 ratings
Positive41.7%
Neutral16.7%
Negative41.7%
Written reviews35 reviews
Positive40.0%
Neutral14.3%
Negative45.7%

Ruler

All ratings3 ratings
Positive66.7%
Neutral0.0%
Negative33.3%
Written reviews27 reviews
Positive63.0%
Neutral3.7%
Negative33.3%

In-app purchases

None

Model Scaler

No in-app purchases

1 purchases

Ruler

One-time1
  • Hide Ads$0.99

Questions

Is Model Scaler free?
Model Scaler is free to download, with no in-app purchases.
Is Ruler free?
Ruler is free to download, with in-app purchases available.
Which has better reviews, Model Scaler or Ruler?
Ruler is rated higher. Model Scaler averages 2.9 out of 5 from 12 ratings, while Ruler averages 3.7 from 3 ratings.
Do Model Scaler or Ruler have ads?
Ruler shows ads; Model Scaler does not.
Which is updated more often, Model Scaler or Ruler?
Model Scaler ships an update every 6 months, and Ruler every 5 months. Most recently, Model Scaler was updated on June 11, 2026 and Ruler on June 1, 2026.

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