Photo Ruler vs Ring Sizer
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Photo Ruler
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Measure flat objects from a photo using a sheet of paper as a reference. Paper Image Meter corrects camera perspective, confirms the paper boundary, traces the object, and calculates useful measurements in millimetres, centimetres, or inches. Image analysis stays on your iPhone. HOW IT WORKS 1. Take a photo or import one from Photos or Files. 2. Choose the paper formatβA4 is selected by default. 3. Confirm the detected paper corners before measurement. 4. Select the object and refine its outline when needed. 5. Review width, height, area, perimeter, paper coverage, and confidence. 6. Save the result or export a polished annotated image or SVG outline. PAPER FORMATS Choose ISO A0βA6, US Letter, Legal, Tabloid, Executive, 4Γ6, 5Γ7, 8Γ10, or enter a custom paper size from 10 to 2000 mm. The app automatically accounts for portrait or landscape orientation after the paper corners are confirmed. CORRECT PHOTOS TAKEN AT AN ANGLE The detected paper quadrilateral is always shown for confirmation. Drag the four corner handles, use the magnified loupe for precise placement, reset the adjustment, or run detection again. The app validates the shape before converting the photographed sheet into a normalized view with a physical pixel-to-millimetre scale. REFINE COMPLEX OBJECTS Start from the automatically detected object, then refine difficult edges with contour nodes or add and erase brushes. Adjust brush size, smooth the result, undo or redo changes, and return to the automatic outline. The editor supports curved edges, holes, concave shapes, fine details, and multiple contour components that belong to the selected object. USEFUL MEASUREMENT RESULTS View rotated bounding width and height, area, perimeter, percentage of the paper covered, and a combined confidence indication. Low-confidence scenes are identified instead of being presented as certain measurements. Save projects locally, reopen them from history, and continue refining without spending another free completed measurement. EXPORT YOUR RESULT Create Clean, Dimensioned, or Report layouts with the object outline and key measurements. Choose whether the date appears on the image, in the report footer, or not at all. Preview the layout, then export an annotated PNG or JPEG, or a standalone SVG/STL outline with physical units. Share through Photos, Files, or the system share sheet. DESIGNED FOR THE RIGHT SCENE For the best estimate, place one flat object completely on one flat sheet of paper. The paper and object must be fully visible and lie on the same plane. Transparent, reflective, folded, heavily shadowed, partially off-paper, three-dimensional, or ambiguous low-contrast scenes may be blocked or shown with a low-confidence warning. Paper Image Meter performs image analysis and measurement processing on your device. It does not require an account, upload photos for processing, or include analytics or advertising SDKs. Measurements are consumer estimates and are not certified for trade, engineering, medical, safety, or other regulated use. For the best estimate, the entire paper and one flat object must be visible, flat, and on the same plane. Results may be inaccurate for folded paper, transparent or reflective objects, heavy shadows, glare, blur, low contrast, objects extending beyond the paper, or three-dimensional objects. Saved measurement projects remain in the app's local container unless you choose to export or share them. Generated exports omit location metadata. Apple may process purchase and subscription information through StoreKit under Apple's terms and privacy practices. Paper Image Meter includes five lifetime free completed measurements. After those uses, an active yearly auto-renewing subscription is required to start another new measurement. Editing, reopening, saving, or exporting an existing measurement does not consume another use. Terms: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy: https://yumcut.com/mobile/privacy
Ring Sizer
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Ring Sizer is a simple on-screen tool to find your ring size at home. Place a ring on the screen and resize the guide until it matches the inner edge, or measure your finger with the stencil and side slider. Ring Sizer also includes a real centimetre and inch ruler. Get clear US, UK, and EU sizes, save measurements on your device, and calibrate with a bank card for better accuracy. This app uses the standard Apple Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: Ring Sizer at none against Photo Ruler's 1. Ring Sizer also leads on iOS requirement (15.1 vs 18.0). On price, update cadence, ads and device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Both are free to download. Photo Ruler sells 1 in-app purchase, starting at $6.99 per year. Ring Sizer asks for nothing beyond the download.
Photo Ruler ships an update weekly, Ring Sizer every 2 weeks. Both last shipped on October 25, 2026.
| Parameter | Photo Ruler | Ring Sizer |
|---|---|---|
| Price | Free | Free |
| Update frequency | Weekly β better | Every 2 weeks |
| Ads | No | No |
| In-app purchases | Yes | No β better |
| Devices | iPhone | iPhone, iPod β better |
| Requires iOS | 18.0 | 15.1 β better |
| Further details β not scored | ||
| Size | 6 MB | 49 MB |
| Age rating | 4+ | 4+ |
| Developer | Ihar Shaduryn | Yaroslav Trofimov |
In-app purchases
Photo Ruler
- Paper Image Meter Unlimited$6.991 Year
Ring Sizer
No in-app purchases









