How accurate is the angle measurement?

Accuracy depends on how precisely you align the guide arms with the edges you're measuring. Under good lighting and with careful alignment, you can typically achieve readings within 1–2 degrees, which is sufficient for carpentry, DIY, and general measurement tasks.

Does it measure the inner or outer angle?

The protractor displays the angle between the two guide arms. If you align them with two surfaces meeting at a corner, you get the interior angle. To find the exterior angle, subtract from 180°.

Can I use it to check a mitre cut before sawing?

Yes — that's one of the most practical uses. Hold your phone so the camera sees the workpiece, align the arms with the cut line and the adjacent face, and read the angle before setting your saw.

Does Protractor need internet access?

No. It uses only your device's camera to display the live feed and processes everything locally. No data is transmitted, no network connection is needed.

Protractor

APP

Measure angles over your live camera feed.

Best on the app

Protractor needs your phone's hardware

It overlays a protractor on your live camera feed. Download Carbide free to use it — plus all 111 tools, fully offline.

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What it does

Protractor overlays a precise angle-measuring tool on your device's live camera feed so you can measure the angle of real-world objects without touching them. Point your camera at a corner, a slope, a staircase, or any angled edge, drag the two guide arms to align with the surfaces you're measuring, and read the angle in degrees instantly. It's ideal for checking mitre cuts before you make them, measuring roof pitch, confirming corner angles in joinery, or any situation where you need an angle reading without a physical protractor. Completely free, offline, and private — nothing leaves your device.

How to use the Protractor

Open Protractor from the Measurement category.
Grant camera permission when prompted — the live viewfinder will appear.
Point the camera at the angle or corner you want to measure.
Drag the two guide arms to align precisely with the two surfaces forming the angle.
Read the angle in degrees shown on screen — tap the result to copy it.

Frequently asked questions

How accurate is the angle measurement?: Accuracy depends on how precisely you align the guide arms with the edges you're measuring. Under good lighting and with careful alignment, you can typically achieve readings within 1–2 degrees, which is sufficient for carpentry, DIY, and general measurement tasks.
Does it measure the inner or outer angle?: The protractor displays the angle between the two guide arms. If you align them with two surfaces meeting at a corner, you get the interior angle. To find the exterior angle, subtract from 180°.
Can I use it to check a mitre cut before sawing?: Yes — that's one of the most practical uses. Hold your phone so the camera sees the workpiece, align the arms with the cut line and the adjacent face, and read the angle before setting your saw.
Does Protractor need internet access?: No. It uses only your device's camera to display the live feed and processes everything locally. No data is transmitted, no network connection is needed.

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