Comparison

Protractor, Level vs Diamond Grader

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

Head to head
About

Protractor, Level

Features
Read full description

Ruler, tape measure, bubble level and protractor. Four measuring tools in one app. Every tool is free. Centimetres and inches are both free. There is no subscription. RULER Measure anything against the edge of your screen. Centimetres and inches are shown at the same time, so there is no toggle to hunt for. Drag to measure, freeze the reading, copy it with one tap. TAPE MEASURE For anything longer than your phone. Measure one screen at a time and Notch adds up the running total as you go, with undo if you slip. BUBBLE LEVEL Lay the phone flat for a two-axis bubble, or hold it against a wall for a single-axis level. Reads in degrees and slope percentage, and buzzes the moment it is level so you do not have to watch the screen. Set your own zero on any surface. PROTRACTOR AND ANGLE FINDER Measure the tilt of a surface and hold the reading while you move the phone. Or drag two arms on screen to measure an angle on paper. ACCURATE, AND YOU CAN CHECK IT Notch knows the exact pixel density of your device, so it is accurate the moment you open it. If you want to verify, calibrate against any bank card. They are the same size in every country. WORKS ANYWHERE No account. No internet connection needed. No tracking, and nothing is sent anywhere. Notch Pro is a one-time purchase that saves your measurements to a history list. The measuring tools stay free forever.

About

Diamond Grader

Features
Read full description

Know what you're looking at. Diamond Grader turns the camera in your pocket into a jeweller's loupe. Photograph a diamond and advanced AI vision examines what your images genuinely show — then tells you, plainly, what they cannot. THE CAPTURE STUDIO A guided camera built for stones. Frame the diamond inside the loupe and get live coaching on light, focus, reflections and framing. The face-up shot is the only one needed. Crown, profile, detail, certificate and UV are optional, and each one raises confidence. YOUR ASSESSMENT • The 4Cs — apparent colour range, clarity range, cut characteristics and carat • Ranges rather than false precision, with a confidence level on every finding • Visible inclusions and blemishes, each labelled by how certain it really is • AI Loupe — zoom deep into your photograph, with findings marked where they were seen • Symmetry, proportions, polish and fluorescence indications • Market insights, given as ranges, in your currency • Buying insights: strengths, concerns, and the questions worth asking a seller • Selling insights: how to describe a stone honestly and position it well • Compare against a grading report you already hold • A shareable report, and your full history kept on your device HONEST BY DESIGN Photographs have limits, and this app says so. Where the evidence isn't there you get "insufficient evidence" rather than a guess. A weight you supply is never overwritten by an estimate. Nothing is ever presented as a certified grade. WHAT THIS IS NOT This is an AI visual assessment of photographs. It is not a laboratory grading report and it is not an appraisal. It cannot determine whether a stone is natural, laboratory-grown, a simulant, or treated — no photograph can. It does not replace physical examination, or a report from an accredited gemmological laboratory. Diamond Grader is not affiliated with, or endorsed by, any gemmological laboratory. LEARN Free, always: the 4Cs, diamond shapes, understanding inclusions, natural versus laboratory-grown, fluorescence, certificates, pricing, buying safely, and how to photograph a diamond well. PRIVACY Photographs you choose to assess are sent over an encrypted connection to an AI provider for processing. You are asked to consent before this happens for the first time, and you can withdraw that consent at any time in Settings. Your photographs, reports and notes are stored on your device. DIAMOND GRADER PRO Assessments are a subscription feature. There are no free assessments and no free trial. • Pro Weekly — billed every week • Pro Monthly — billed every month • Pro Annual — billed every year (best value) Pricing is shown in your local currency inside the app, before any purchase is made. Pro unlocks unlimited assessments, the AI Loupe, market insights, certificate comparison, shareable reports and your full assessment history. Payment is charged to your Apple Account at confirmation of purchase. Subscriptions renew automatically unless auto-renew is turned off at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours prior to the end of the current period. You can manage or cancel your subscription in your Apple Account settings. Privacy Policy: https://angelapplications.co.uk/privacy-policy/ Terms of Use: https://angelapplications.co.uk/terms-of-use/ Standard EULA: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Questions or feedback: contact@angelapplication.co.uk

Screenshots

Protractor, Level2 screens
Diamond Grader4 screens

Verdict

The call

Protractor, Level and Diamond Grader are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS

CostPrice Ā· In-app purchases Ā· Ads Ā· Monetization

Both are free to download. Protractor, Level sells 1 one-off in-app purchase and Diamond Grader sells 3 in-app purchases, starting at $6.99 per 7 days. Whichever you choose, the download price is not the number that matters.

ScorecardNo meaningful differences
Protractor, Level versus Diamond Grader: the parameters behind the verdict, then further details
ParameterProtractor, LevelDiamond Grader
PriceFreeFree
Update frequencyFortnightly—
AdsNoNo
In-app purchasesYesYes
DevicesiPhoneiPhone
Requires iOS17.0 — better18.0
Further details — not scored
Size2 MB7 MB
Age rating4+4+
DeveloperStreamlined StudiosAngel App Publishing Ltd.

In-app purchases

1 purchases

Protractor, Level

One-time1
  • Notch Pro$2.99
3 purchases

Diamond Grader

Subscriptions3
  • Weekly Subscription$6.997 Days
  • Monthly Subscription$12.991 Month
  • Annual Subscription$59.991 Year

Questions

Is Protractor, Level free?
Protractor, Level is free to download, with in-app purchases available.
Is Diamond Grader free?
Diamond Grader is free to download, with in-app purchases available.
Do Protractor, Level or Diamond Grader have ads?
Neither Protractor, Level nor Diamond Grader shows ads.

Other comparisons