Features
Feature explanations for accurate angle measurement, practical workflows, and more reliable results
Free covers the complete basic workflow with one image and one protractor. Plus adds multiple objects, overlays, advanced exports and last-workspace recovery; Pro adds local projects and PDF reports.
Ray-Based Angle Measurement
Place rays directly from the protractor center to measure the angle you actually want to read, then switch between degrees and radians, inner and outer angles, and decimal precision. This is useful when you need to verify homework, compare diagram annotations, or check whether a drawing matches an expected value instead of relying on a rough visual estimate.
Image Upload & Overlay
Upload photos, worksheets, screenshots, blueprints, or technical diagrams and measure directly on top of them. Opacity, resize, and rotation controls help you line the protractor up with the source image more carefully. For best results, use clear images with minimal perspective distortion, because blurry or heavily angled photos can reduce measurement confidence.
Multiple Protractors
Available in Plus and Pro. Use multiple protractors when one image contains several corners or reference lines, so you can compare angles side by side instead of resetting the Free one-protractor workspace.
Flexible Export Options
Every plan includes manual JSON backup and 1x PNG. Plus and Pro add CSV, JPEG, overlay-only and 2x/4x image exports. Pro also generates a PDF report. The plan matrix identifies each format before purchase.
Undo & Redo
Undo and redo let you experiment without losing your place. If you move a protractor, rotate an image, or adjust the wrong ray, you can quickly step backward and compare versions instead of rebuilding the whole setup. This is especially useful while learning the tool or refining a precise reading.
Grid & Ruler Overlays
Available in Plus and Pro. Grid and ruler overlays help align baselines and compare positions. They are reference aids, not proof of physical accuracy or calibration.
Angle Snapping
Available in Plus and Pro. Angle snapping helps with expected values and repeated constructions, but should be disabled when inspecting an irregular angle so it is not forced toward a preset.
Keyboard Shortcuts
Keyboard shortcuts keep repeated measurement work moving quickly. Switch tools, undo changes, and clean up selections without leaving the canvas, which is especially useful when you are checking many angles in one worksheet, diagram set, or annotated image.
View Controls
Zoom and pan controls help you inspect small vertices, crowded intersections, and low-contrast image details before committing to a reading. They make alignment easier, but they do not fix poor source quality, so combine them with clear images and careful center placement for the most reliable results.
Customizable Display
Adjust colors, scale, rotation, and display settings so the protractor stays readable against dark photos, bright diagrams, or busy layouts. These controls are most valuable when you are presenting measurements to others or comparing several angles in the same workspace.
Lock Objects
Lock finished protractors, rays, or images when one part of the workspace is already correct and you only want to adjust the rest. This reduces accidental edits and makes it easier to compare a stable reference angle with a second measurement.
Private & Secure
Measurement images, workspaces and local projects stay in your browser during normal use. Umami loads automatically, GA4 loads when configured, and optional account/payment records are handled as described in the Privacy Policy.
Ready to use these features on real measurements?
Start with Free without an account. Compare the one-time Plus and Pro plans only if you need multiple objects, advanced exports, local recovery, project management or professional reporting.