Getting Started

Start by recognizing the three areas you will use most often. The left toolbar is for actions such as Select (V), Measure Angle (M), and Pan View (Space). The center canvas is where you place protractors, rays, and images. The right panel changes based on what you select and gives you the precise controls for position, scale, display, and statistics. A common beginner mistake is to click around without noticing which object is selected, then change the wrong setting. Before making adjustments, confirm the correct protractor or ray is highlighted. If you can identify where to select, where to place measurements, and where to fine-tune settings, you are ready for the rest of the guide.

Click the '+' button in the Protractor panel to place your first protractor on the canvas. It appears near the center so you can start working immediately. If you are measuring from an uploaded image or diagram, move the protractor close to the angle you care about before doing anything else. New users sometimes leave the protractor in the middle of the screen and start drawing rays too early, which makes the first measurement harder than it needs to be. At this stage, the simple check is whether the protractor is visible, selected, and close enough to the angle vertex that you can align it comfortably in the next step.

Switch to the Select tool (V) and click the protractor so the selection outline appears. Your main goal here is to place the center point of the protractor exactly on the angle vertex, then rotate it so the baseline roughly follows one side of the angle. You can drag for quick positioning or use the panel controls for more exact movement, rotation, and scale. The most common error is lining up the outer edge of the protractor instead of its center point, which leads to a bad reading even if the rays look close. A good self-check is to zoom in and verify that the center mark sits directly on the corner where the two lines meet.

With the protractor selected, choose Measure Angle (M). Place the first ray along one visible side of the angle, then place the second ray along the other side. The measurement label appears automatically once both rays are in place. For the cleanest result, click as if you are tracing the actual edges you want to measure rather than estimating from empty space. Beginners often place one ray slightly off the line or forget which side of the angle they intended to measure, especially on crowded images. If the number looks wrong, first check the ray alignment and the vertex position before assuming the tool is incorrect.

By default, the tool shows the inner angle, which is usually the value most beginners expect. If you need the larger reflex angle instead, click the measurement value to toggle to the outer angle. You can also switch between degrees and radians in the Statistics panel and adjust decimal precision based on whether you need a rough classroom answer or a more technical reading. A common source of confusion is thinking the tool is wrong when it is simply showing the other valid angle or a different unit. The easiest check is to compare the displayed value with what you expect visually: an acute angle should not read like a reflex angle unless you intentionally switched to the outer measurement.

Use the appearance controls to make the measurement easier to read instead of leaving everything at the default settings. Changing color helps when you have multiple protractors or rays on screen, while opacity is especially useful when the source image has dark lines underneath the protractor. Scale matters too: if the protractor is too large or too small for the diagram, the labels become harder to interpret. A frequent beginner mistake is keeping the protractor fully opaque over a busy image, then struggling to see the underlying angle. If you can clearly see both the source line and the ray you are placing, your visual setup is probably good enough.

After placing rays, return to Select (V) whenever you need to refine or clean up the measurement. Click a ray to adjust it, recolor it, or delete it if it was placed on the wrong line. Because all rays start from the protractor center, small errors at the beginning can affect the final angle more than you expect. New users sometimes keep adding extra rays instead of correcting the inaccurate one, which makes the workspace harder to read. A better workflow is to keep only the rays that support the result you actually want to save or export, and to use undo or delete as soon as you notice a mistake.

When the measurement looks right, save it in the format that matches your next step. Export JSON if you want to reopen the exact workspace later with the same protractors, rays, and settings. Export CSV if you only need the numbers for notes or spreadsheets. Export PNG or JPEG if you want a shareable image for homework, documentation, or discussion. Your workspace is also usually preserved locally in the browser, but important work should still be backed up with an export because browser storage can be cleared. You do not need an account to measure or export, and sign-in only matters for account-related actions such as remembering the optional one-time ad-free upgrade.