Comparison

Flying Ruler vs Ring Sizing

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

Head to head
About

Flying Ruler

Measure distances and angles using your device's sensors. This app functions as a ruler, tape measure, rangefinder, protractor, and 3D angle finder, offering a quick and accurate way to take measurements in various conditions.

Highlights
  • Measure distance by moving device
  • Ruler, tape measure, rangefinder
  • Protractor and 3D angle finder
  • Inertial navigational system technology
  • Adjustable units (inches/cm)
  • Save measurements with photos
  • Avoid obstacles during measurement
Read full description

The Flying Ruler app allows you to measure in the most original way: by just moving your device from one point to another. Flying Ruler is a ruler, tape measure, rangefinder, protractor and a 3D angle finder. It is five devices in one app, providing you with the quickest way to measure a distance or an angle. The secret of the program is that it is based on the principles of the inertial navigational system (INS): the position of the device is determined with the help of the accelerometer and the gyroscope. Measurements take place extremely quickly and at the same time they are quite accurate. We are constantly improving our computational algorithm for more than 11 years! To try this technology for free you can install the app "Digital Angle Finder: 3D Meter". This free app measures the angle as you move the device. AWARDS: Editor's Choice — 148Apps www.148apps.com/reviews/flying-ruler-review PRESS ABOUT US: "I was impressed with Flying Ruler’s accuracy. It works quickly and effectively", "It’s the perfect addition to anyone’s app collection" — 148apps 4.5 / 5 (MUST HAVE) "This thing is awesome" — brettterpstra.com "I literally said “wow!” when I first used this app and I think it’s a truly impressive marvel of mobile technology", "The Flying Ruler Rules" — AppPicker (Cons: there is nothing negative to say about this app) *** Measure distance with good precision, no matter the lighting or conditions *** The app has different modes so you can choose which mode is better and easier to use on each occasion. You can measure with the body of the device in one mode or with a virtual tape measure in another. You can not only measure an object but also the distance between two walls (rangefinder mode). You use the same methods to measure angles as the app allows you to measure angles both on a surface area (protractor mode) and between surfaces through space (3D angle finder mode). You can choose either inches or centimeters. The maximum distance is only limited by the value of the indicator which consists of 999 ft for the imperial system and 99 m for the metric system. When measuring, you can avoid obstacles and therefore you can measure anything. Flying Ruler is suitable for measuring not only large, but also very small distances with the accuracy of a standard ruler. The app also allows you to save a measurement by taking a photograph of the measurement and mark the place that was measured. Don’t forget to show your friends and colleagues how the app works – believe us, they will be impressed. ACCURACY OF MEASUREMENT: We took 100 consecutive measurements and got these results: On iPhone 13: • Mean squared error - 0.14% • Maximum inaccuracy - 0.4% On iPhone 7: • Mean squared error - 0.15% • Maximum inaccuracy - 0.4% On iPhone 6s: • Mean squared error - 0.28% • Maximum inaccuracy - 1.1% The accuracy of measurements depends on the device, however the error rarely exceeds 1.5%. You can always increase accuracy by making a series of measurements. If you make a series of measurements, the degree of error is usually 0.3% or less. Angles can be measured with the app to an accuracy of one degree so the app can easily take the place of a protractor or a angle finder. WEBSITE: www.flying-ruler.com

About

Ring Sizing

Accurately measure ring sizes using your phone's screen. Determine diameter, circumference, and convert between international sizing systems. Ideal for jewelers and shoppers needing precise measurements.

Highlights
  • Measure ring diameter on screen
  • Determine circumference in mm/inches
  • Pacher method calculation
  • International size conversion (EU, US, UK, JP)
  • Precise slider for measurement
Features
Read full description

Ring Size Find the perfect ring size quickly and accurately. Ring Size makes it easy to determine the correct ring size for yourself or someone special. Simply place a ring directly on your iPhone or iPad screen and adjust the on-screen circle with the slider until it perfectly matches the inside diameter of your ring. The app instantly calculates all important measurements and converts them into the most common international ring size standards. Features • Measure ring size directly on your screen • Precise diameter adjustment with an easy slider • Calculate ring circumference in millimeters and inches • Display the inside diameter • International ring size standards: * European sizes * US sizes * UK sizes * Japanese sizes • Supports the Pacher sizing method • Fast, accurate and easy to use • Perfect for jewelry shopping, jewelers and goldsmiths Whether you're buying an engagement ring, wedding band or fashion jewelry, Ring Size helps you find the perfect fit and avoid costly mistakes. An essential tool for online jewelry shopping and professional use.

Screenshots

Flying Ruler4 screens
Ring Sizing4 screens

Verdict

The call

The clearest difference is price: Ring Sizing at Free against Flying Ruler's $1.99. Flying Ruler's advantage is rating (4.1 vs 1.0) and ratings volume (186 vs 1). On 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

CostPrice · In-app purchases · Ads · Monetization

Ring Sizing is free to download; Flying Ruler costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Flying Ruler holds the better App Store score, 4.1 against 1.0. That said, the two scores are not equally well evidenced: Flying Ruler has 186 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Flying Ruler ships an update every 2 months, Ring Sizing every 10 months. The most recent releases landed on October 29, 2026 and October 12, 2026 respectively.

Scorecard6 real differences · 4 level
Flying Ruler versus Ring Sizing: the parameters behind the verdict, then further details
ParameterFlying RulerRing Sizing
Price$1.99Free — better
Rating4.1 (186 ratings) — better1.0 (1 ratings)
Positive reviews86.3% of reviews—
Number of ratings186 — better1
Update frequencyEvery 2 months — betterEvery 10 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better26.0
Further details — not scored
Size78 MB10 MB
Age rating4+4+
DeveloperALEXEY BRILEVGerhard Lentschik

Customer experience

Flying Ruler

All ratings186 ratings
Positive81.2%
Neutral4.3%
Negative14.5%
Written reviews461 reviews
Positive86.3%
Neutral4.6%
Negative9.1%

Ring Sizing

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%

Bugs and requests

Flying Ruler

Reported bugs

3 issues
  • Measurements vary wildly between attempts
  • Calibration process fails to complete
  • App crashes when used with certain phone cases

Requested features

4 requests
  • Add imperial unit support
  • Integrate with smart home devices
  • Provide more advanced measurement tools
  • Improve accuracy for smaller distances

Ring Sizing

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Flying Ruler

No in-app purchases

None

Ring Sizing

No in-app purchases

Questions

Is Flying Ruler free?
Flying Ruler costs $1.99, with no in-app purchases.
Is Ring Sizing free?
Ring Sizing is free to download, with no in-app purchases.
Which has better reviews, Flying Ruler or Ring Sizing?
Flying Ruler is rated higher. Flying Ruler averages 4.1 out of 5 from 186 ratings, while Ring Sizing averages 1.0 from 1 ratings.
Do Flying Ruler or Ring Sizing have ads?
Neither Flying Ruler nor Ring Sizing shows ads.
Which is updated more often, Flying Ruler or Ring Sizing?
Flying Ruler ships an update every 2 months, and Ring Sizing every 10 months. Most recently, Flying Ruler was updated on October 29, 2026 and Ring Sizing on October 12, 2026.

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