Ruler vs 100cm Ruler
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
100cm Ruler
This app provides a digital ruler for measuring the length and diameter of small objects directly on your device. It features a millimeter scale and allows for easy sliding to measure.
- Digital ruler functionality
- Millimeter scale
- Diameter measurement
- Screen sliding for measurement
- Ad removal option
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Plotting scale is useful to measure the length of small articles and insects. Squared in millimeters on the lower left, thus the diameter can be measured roughly. Hold the screen and slide your iPhone to the right. https://www.youtube.com/watch?v=kxU9xi88IiY Ads can be removed on "Info page".
Screenshots
Verdict
The clearest difference is ads: 100cm Ruler at none against Ruler's shown. 100cm Ruler also leads on rating (4.0 vs 3.7) and iOS requirement (12.0 vs 15.0). Ruler's advantage is review sentiment (63% vs 45%) and ratings volume (3 vs 1). On price, update cadence, in-app purchases and monetization model 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 and 100cm Ruler sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
100cm Ruler holds the better App Store score, 4.0 against 3.7. Both are backed by a comparable volume of ratings — 3 and 1 respectively. Written reviews complicate that: 63% of Ruler's written reviews are positive against 45% of 100cm Ruler's, so the app with the better star average is not the one people write more warmly about.
Ruler ships an update every 5 months, 100cm Ruler every 3 months. The most recent releases landed on June 1, 2026 and June 11, 2026 respectively.
| Parameter | Ruler | 100cm Ruler |
|---|---|---|
| Price | Free | Free |
| Rating | 3.7 (3 ratings) | 4.0 (1 ratings) — better |
| Positive reviews | 63.0% of reviews — better | 45.1% of reviews |
| Number of ratings | 3 — better | 1 |
| Update frequency | Every 5 months | Every 3 months — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 15.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 4 MB | 62 MB |
| Age rating | 4+ | 4+ |
| Developer | mitsunori oishi | ZOOMO, Inc. |
Customer experience
Ruler
100cm Ruler
In-app purchases
Ruler
- Hide Ads$0.99
100cm Ruler
- Remove ADS$1.99







