Ruler vs Image 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.
Image Ruler
This app allows you to measure objects directly on photos. Simply take a picture, mark a known object for reference, and then draw measurements on other items within the same image. It supports both metric and imperial units and offers intuitive editing tools.
- Measure objects on photos
- Use a known object as a reference
- Supports metric and imperial units
- Intuitive editing interface
- Organize photos easily
- Zoom for precision
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Measure anything in any photo. Take a photo or import one from your library, place a reference object you already know the size of, and instantly calculate real-world measurements — lengths, angles, and areas — directly on the image. How it works Set a reference line on a known object in your photo. From there, every measurement you draw is automatically calculated in real scale. What you can measure Ruler — measure distances and lengths Arrow — annotate with directional measurements Angle — measure the angle between any two lines Area — tap points to outline a surface and calculate its area Built for precision Works entirely offline — no internet required Metric and imperial units Pinch to zoom for precise point placement Undo and redo any change Hide or show your reference line at any time Tips for accurate results For best accuracy, make sure your reference object and the object you're measuring are in the same plane, and that the camera was parallel to both when the photo was taken. Perspective distortion affects results. Measurements are estimates based on the reference you provide.
Screenshots
Verdict
The clearest difference is review sentiment: Ruler at 63% against Image Ruler's 18%. Ruler also leads on rating (3.7 vs 1.6). Image Ruler's advantage is update cadence (every 3 weeks vs every 5 months) and monetization model (free vs free with in-app purchases). On price, ads, in-app purchases 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 and Image Ruler sells 5 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.
Ruler holds the better App Store score, 3.7 against 1.6. That said, the two scores are not equally well evidenced: Image Ruler has 45 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 63% of Ruler's written reviews are positive against 18% of Image Ruler's.
Ruler ships an update every 5 months, Image Ruler every 3 weeks. The most recent releases landed on October 21, 2026 and October 24, 2026 respectively.
| Parameter | Ruler | Image Ruler |
|---|---|---|
| Price | Free | Free |
| Rating | 3.7 (3 ratings) — better | 1.6 (45 ratings) |
| Positive reviews | 63.0% of reviews — better | 17.6% of reviews |
| Number of ratings | 3 | 45 — better |
| Update frequency | Every 5 months | Every 3 weeks — better |
| Ads | Yes | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 4 MB | 47 MB |
| Age rating | 4+ | 4+ |
| Developer | mitsunori oishi | Martin Schurmann |
Customer experience
Ruler
Image Ruler
In-app purchases
Ruler
- Hide Ads$0.99
Image Ruler
- imageRulerPro$0.99
- Small Tip2 variants$0.99
- Medium Tip2 variants$2.99
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- Big Tip$4.99
- Big tip$4.99
Questions
Is Ruler free?
Is Image Ruler free?
Which has better reviews, Ruler or Image Ruler?
Do Ruler or Image Ruler have ads?
Which is updated more often, Ruler or Image Ruler?
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