Tested in November 2026. The scoring was checked with computer-drawn strokes: a clean circle, a wobbly one, an open one, a tiny one and a straight line. It has not been tried by many people on many phones, so treat the score as a fun guide, not a measurement.
How to play Draw a Perfect Circle
- Press Play now.
- Press and hold on the dark board with your finger or mouse.
- Draw one circle in a single stroke and try to end where you started.
- Lift your finger. The tool fits the best circle to your line and shows it as a green dashed ring.
- Check your roundness score, then play again to beat your personal best or share the score card.
How the score is worked out
| Part | What it means |
|---|---|
| Roundness | How far your line wanders from the best fitting circle. A smaller wobble gives a higher score. |
| Closing gap | If the start and the end do not meet, points are taken off. |
| Full turn | You must go all the way round. Half circles are rejected so you can try again. |
| Size | Very small circles are rejected because tiny shapes are too coarse to judge. |
Tips to score higher
- Draw at a steady speed. Slowing down makes the line shaky.
- Move your whole arm or wrist, not only your fingertip.
- On a phone, rest your hand on the screen edge for support.
- Use the dot in the middle of the board as the centre of your circle.
- A mouse or a stylus usually scores higher than a finger.
Limits to know about
- The score is a game, not a medical or art test.
- Results depend on your screen size and how your device reports touches.
- Your best score is saved in this browser only. Clearing site data removes it.
Privacy
The game runs in your browser. Your drawing is never uploaded. Only your best score and sound choice are stored on your device.
Frequently asked questions
How is the roundness percentage calculated?
The tool fits a circle to your stroke, measures how far each point is from that circle and turns the average wobble into a score from 0 to 100.
Why was my circle rejected?
It was too small, too short, nearly straight or not a full turn. The message on the board tells you which one.
What is a good score?
Above 90 is very good. Above 95 is hard to reach by hand. Above 98 is rare.
Can I share my score?
Yes. After a round press Share score card. You get a picture you can send, download or post.
Does it work on a phone?
Yes. Draw with your finger. The page does not scroll while you draw on the board.
Draw a Perfect Circle is a free game from ToolsRiver. No sign-up, no ads inside the game, and it works on phones, tablets and computers. More free games are in the Gaming Tool section.