Comparison

Protractor vs Trueline

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

Head to head
About

Protractor

Features
Read full description

PAID ACCESS REQUIRED Protractor is a paid app. A weekly or yearly auto-renewable subscription, or a one-time lifetime purchase, is required to use every feature after onboarding. There is no free version and no free trial. Measure any angle without a physical protractor. Drag two arms across the screen, aim the camera at a real object, or rest your phone on a slope and read the tilt live. Most angle apps give you one trick. Protractor gives you three measuring surfaces in one app — an on-screen protractor for photos and drawings, a see-through camera overlay for real objects, and a motion-sensor inclinometer for surfaces you can put your phone on. Every reading comes out in degrees, radians or percent grade, and roof work gets the rise-in-12 pitch on the same screen. WHAT YOU GET - Read the exact degree of any corner on a photo or drawing by dragging two arms and the vertex onto it - Point the camera at a wall, ramp, roof edge or shelf and measure the angle right on the live view - Turn your phone into a digital level that shows pitch, roll, percent grade and roof pitch as rise:12 at once - Lock a reading with Hold or Freeze so the number stays put while you climb down or move the phone - Keep every measurement in History with a photo thumbnail, plus your saved count, average and widest angle - Switch between degrees, radians and grade in one tap, with a built-in conversion table for common values PERFECT FOR - DIY and home projects: shelves, picture rails, ramps, furniture - Roofing, decking and construction: slope, grade and pitch checks - Woodworking and metalwork: bevels, miters and corner angles - Students and teachers measuring angles on diagrams and photos WHY NOT JUST USE A PLASTIC PROTRACTOR A plastic protractor only works on paper, only reads what fits inside its arc, and is never in your pocket when the roof needs checking. This one measures on a photo, through the camera, or straight off a surface — and it remembers every reading instead of you writing them on a scrap of wood. PRIVACY Everything is measured and stored on your device. No account, no sign-up, no cloud upload of your photos or readings. The camera feed is used only to draw the protractor on top of it, and the app works with no internet connection. FULL ACCESS Full access unlocks the camera protractor, the live inclinometer, saved measurement history and all angle units. It is offered as a weekly subscription, a yearly subscription, or a one-time lifetime purchase. Your exact plan and price are shown before you confirm, and subscriptions renew until cancelled in your App Store settings. Open Protractor, point it at the next angle you need, and get the number in seconds. Terms of Use (EULA): https://web-levi.web.app/terms Privacy Policy: https://web-levi.web.app/privacy-policy Questions? Email tphuc.work@gmail.com

About

Trueline

Features
Read full description

Trueline turns your iPhone into a level that behaves like a real instrument — quiet, readable, and honest about what it measures. Free: • Auto-switching modes — on edge or plumb you get a vial with a signed degree readout; laid flat it becomes a 2-axis bullseye surface level • Read in degrees, slope %, or roof pitch (rise per 12) • One-tap calibration • HOLD freezes a reading you can't see from where you're standing • ZERO for relative angles — the angle between two surfaces • Haptic snap and a green edge glow the moment you're level • Fully offline, no account Pro — one payment of $6.99, no subscription: • AR laser level: project gravity-true level and plumb lines onto the wall and hang a whole row of frames in one pass • Named angle presets — 4/12 and 6/12 roof pitch, stair rake, 2% drainage • Precision tolerance down to ±0.1° • 5 instrument themes • No ads Pay once, yours forever. No subscription, no sign-in, and nothing leaves your phone.

Screenshots

Protractor4 screens
Trueline4 screens

Verdict

The call

The clearest difference is ads: Protractor at none against Trueline's shown. Trueline's advantage is update cadence (daily vs every 6 weeks). On price, in-app purchases, device support and iOS requirement there is nothing between them.

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 sells 3 in-app purchases, starting at $4.99 per 7 days and Trueline sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Protractor ships an update every 6 weeks, Trueline daily. The most recent releases landed on September 24, 2026 and September 15, 2026 respectively.

Scorecard2 real differences Ā· 4 level
Protractor versus Trueline: the parameters behind the verdict, then further details
ParameterProtractorTrueline
PriceFreeFree
Update frequencyEvery 6 weeksDaily — better
AdsNo — betterYes
In-app purchasesYesYes
DevicesiPhoneiPhone
Requires iOS17.017.0
Further details — not scored
Size5 MB12 MB
Age rating4+4+
DeveloperPhuc PhamEdge Analytics s.r.o.

In-app purchases

3 purchases

Protractor

Subscriptions2
  • Incline Gauge Weekly$4.997 Days
  • Roof Pitch Yearly$24.991 Year
One-time1
  • Bevel & Degree, Pay Once$49.99
1 purchases

Trueline

One-time1
  • Trueline Pro$6.99

Questions

Is Protractor free?
Protractor is free to download, with in-app purchases available.
Is Trueline free?
Trueline is free to download, with in-app purchases available.
Do Protractor or Trueline have ads?
Trueline shows ads; Protractor does not.
Which is updated more often, Protractor or Trueline?
Protractor ships an update every 6 weeks, and Trueline daily. Most recently, Protractor was updated on September 24, 2026 and Trueline on September 15, 2026.

Other comparisons