Digital Angle Finder & Protractor Tool

Measure angles instantly with our free online digital angle finder and protractor angle finder tool. Use the interactive protractor on screen, upload photos to use as a triangle angle finder, use a live camera overlay, or check slope.

Camera & Level No Upload Free Forever Private
Angles Summary
Angle #1
120°
Reflex Angle
Alignment & Locks
Gravity Auto-AlignLevel base using gyro sensor
Protractor Scale
Lock Line Grips
Lock Line 1
Lock Line 2
Line Positions (Manual)
Line 1 position
deg
Line 2 position
deg
Angles delta (Manual)
Angle #1 (Delta)
deg
Snap Increment
Instructions & Usage Tips

Protractor Mode: Measure central angles by dragging colored line handles. Click "+ Add Line" to add up to 6 lines and measure consecutive angles radiating from the center pivot. Lock individual line handles to protect reference bearings from accidental movements. Toggle auto-align to sync the baseline automatically using your phone accelerometer.
Why Arovat

Everything competitors are missing.

Drag-to-measure protractor

Drag the blue and purple handles anywhere on the 360° protractor. Snap to 0.1°, 1°, 5°, 10°, 45°, or 90° increments.

Live camera + capture

Point your phone camera at any angle, capture a freeze-frame, and measure it precisely on the protractor.

Measure angles on photos

Upload any image, a roof, a triangle, a technical drawing, and overlay the protractor directly on top.

Spirit level

Uses your device's motion sensor to show real-time tilt. Calibrate to any reference surface. Perfect for contractors.

Angle history & export

Save as many measurements as you need. Export an annotated PNG or copy a shareable URL encoding your angle.

100% private

Everything runs in your browser. No images, no data, no measurements ever leave your device.

How it works

Three modes. One tool.

01 — Protractor

Drag lines to measure

Two draggable arms snap to your chosen increment. Upload a photo and the protractor overlays directly on your image.

02 — Camera

Point, capture, measure

Tap Start Camera, point at your subject, and hit Capture. The freeze-frame loads into the protractor for precise measurement.

03 — Spirit Level

Real-time tilt sensor

Uses your device's accelerometer. Place flat and calibrate, then tilt to read the exact angle from level in real time.

Free Digital Angle Finder & Protractor Angle Finder Tool

Whether you're a professional carpenter checking a miter cut, a student solving high-school geometry, or an engineer analyzing structures on a photograph, our free online angle finder tool gives you pinpoint accuracy without installing any software or app. The entire digital angle finder runs locally in your web browser, keeping your data, photos, and measurements 100% private.

Interactive Protractor Angle Finder Tool

The protractor angle finder mode displays two draggable arms over a full 360° circular grid. Simply drag either control handle to match any slope, and the angle updates in real-time. Lock the snapping controls to 0.1°, 1°, 5°, 10°, 45°, or 90° increments to make drawing and measuring simple. You can also toggle reflex angle mode (measuring angles larger than 180 degrees) or easily convert measurements between degrees and radians.

Photo & Triangle Angle Finder Mode

Need to measure a pitch from a photo? Our triangle angle finder feature lets you upload any image (such as a roof slope, a staircase truss, or a engineering schematic) and overlay the virtual protractor directly on top. By positioning the vertices of the measurement handles over the image, you can measure geometric shapes and triangles within seconds. Your uploaded photos are processed strictly client-side and are never sent to a server.

Live Camera Digital Angle Finder

Take your measurements on the go. Switch to Camera mode on any mobile device to activate your rear-facing camera. Align the live overlay lines with any physical edge or structure, and tap Capture to lock a freeze-frame directly inside the protractor canvas. If you start on a desktop, our built-in QR code handoff allows you to instantly scan and transfer the session to your smartphone's web browser.

Contractor-Grade Digital Spirit Level

Use the built-in accelerometer in your phone or tablet to turn Arovat into a high-precision digital angle finder and level. The liquid-bubble interface animates smoothly to indicate pitch and tilt in real time. Use the Calibrate feature to establish a custom zero-reference plane, allowing you to accurately measure relative slopes even on uneven ground.

Save, Export, and Share Your Angles

Keep track of multiple measurements with our automatic history log. Label your saved angles for quick reference, export annotated screenshots as PNG files for reports, or generate a shareable URL that encodes your exact angle data to send to colleagues. It's the ultimate browser-based angle finder tool designed for privacy, convenience, and speed.

Angle Finder Feature Summary:

  • Protractor Angle Finder: Draggable 360-degree arms with precision snapping (0.1° to 90°).
  • Triangle Angle Finder: Instant image uploading with custom overlay alignment for complex triangles.
  • Digital Angle Finder: Live device camera alignment and accelerometer tilt scanning.
  • Digital Spirit Level: Bubble level visualizer, relative calibration, and degree/radian readouts.
  • Measurement Exports: History log preservation, URL-encoded sharing, and high-res PNG downloads.
  • 100% Client-Side Privacy: Zero uploads, zero tracking, works fully offline after your first visit.

Frequently Asked Questions

Do I need an angle finder, or can I use my smartphone?
You do not need to buy expensive hardware. Your smartphone works perfectly as a digital angle finder. Arovat utilizes your mobile device's camera stream and built-in motion sensors to measure slopes, draw circles, and check levels directly in your web browser.
Can an angle finder be used to check if a wall is perfectly square?
Yes. You can place your phone flat against the corner or wall and check its alignment using the spirit level or protractor mode to see if it is a true 90-degree square. For complex setups, snap a photo and use our triangle angle finder mode to calculate the angle on your screen.
How do I calibrate or reset a digital angle finder?
In Spirit Level mode, place your smartphone flat on a known level reference surface and tap the Calibrate button. This sets the current surface as your 0-degree baseline. Tap Reset to clear the custom offset and restore absolute accelerometer calibration.
How do I measure an irregular corner?
To measure irregular corners, use our image upload tool. Take a photo of the area, load it into Arovat, and overlay our virtual protractor angle finder. Drag the alignment handles to trace the walls, giving you the exact angle within seconds.
What is the difference between an analog and digital angle finder?
Analog protractors require aligning physical marks and manually reading values, which can introduce errors. A digital angle finder uses optical sensors or accelerometers to show real-time numerical readings on an digital screen with high accuracy and precision.
does this work on desktop?
Yes, all features except the motion-controlled level work on desktop. You can use the 360-degree protractor, upload photos to measure shapes, and export history. Arovat also provides a QR code so you can easily hand off the session to a mobile phone when level sensors or cameras are required.
how accurate is the angle measurement?
On screen (protractor and photo modes), the resolution is accurate down to 0.1 degrees. In spirit level mode, accuracy depends on your mobile device's accelerometer calibration, generally delivering results within a margin of 0.1° to 0.5°.
is sensor mode required?
No. Device sensor permission is only needed for the spirit level. You can use the virtual protractor, camera overlay, QR code tools, and image uploads without enabling sensor access.
can i measure reflex angles?
Yes, Arovat supports reflex angle calculation. Simply check the reflex option inside the settings panel to measure angles greater than 180 degrees (up to 360 degrees), perfect for measuring outer corners.