Draw a circle with your mouse or finger. We'll measure how perfect your circle is!
Draw a circle here!
Drag with mouse or finger
It's a game where you freely draw a circle with your mouse or finger, and the accuracy is measured mathematically. A standard deviation-based algorithm compares your drawing to a perfect circle and shows accuracy as a percentage.
The center point of all drawn points is calculated, then the standard deviation of distances from each point to the center is computed. The closer the standard deviation is to 0, the more perfect the circle, resulting in a score closer to 100%.
The guide circle is a faint dashed circle displayed in the center of the canvas. Drawing along it helps you achieve a more accurate circle. You can toggle it on and off in the options.
Best records are automatically saved in your browser's localStorage. When you revisit on the same browser, your previous best record will be displayed.
The Perfect Circle Drawing Test is a fun game where you freely draw a circle using your mouse or touch, and the accuracy is measured using a mathematical algorithm. Check your hand precision with standard deviation-based measurement.
This tool uses mathematical methods including center point calculation, average radius measurement, and standard deviation analysis to accurately evaluate the completeness of your drawn circle. Score 95% or above to earn the 'God\'s Hand' grade.
Features include guide circle display, circle size adjustment, and best record saving. Share with friends to compete on who can draw the most perfect circle. Works on both PC and mobile devices.