Perfect Circle Test

Draw a circle freehand with your mouse or finger and score how round it is, then see a colour-coded map of every wobble in your stroke.
Score
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Best
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Wobble
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Attempts
0
Practice — doesn't count
Result
＼(^o^)／ New personal best!
Score
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Wobble
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Radius
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Sweep
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Your hand-drawn circle with each segment coloured by how far it sits from a perfect circle
on the ideal radius drifting well off the perfect circle
Recent attempts

Features

  • Draw a circle freehand with the mouse, a trackpad, or your finger
  • Scored with a least-squares circle fit, so the result is the real geometry, not a guess
  • Wobble percentage showing how far your radius drifted from the ideal
  • Colour-coded stroke: green where you held the radius, red where you bulged or cut in
  • The circle you were aiming for drawn over the top as a dashed ring
  • Download your attempt as a PNG to share
  • A live tone that bends with your wobble, so you can hear the error as you draw
  • Guide ring practice mode for tracing, kept out of your best score
  • Half circles, scribbles, and tiny circles are rejected rather than rewarded
  • Best score and your last five attempts saved locally
  • One-click mute, remembered between visits

How to Use

  1. Press and hold anywhere on the white pad.
  2. Drag all the way around in one continuous stroke — a partial arc will not be scored.
  3. Release to see your score. Extra laps are ignored, so only the first full turn counts.
  4. Check the coloured stroke: green means you held the radius, red means you drifted off it.
  5. Turn on the guide ring to practise by tracing — those attempts are shown but never recorded.
  6. Use the speaker button to mute the tone that tracks your wobble.
  7. Press Download circle to save the image, or Enter to clear and try again.