Drill 01Freehand circle
How to draw a circle freehand
Draw one circle. Get a number, and the reason behind it.
Measures your line, not your drawingRuns on your deviceFree and unlimitedWant a real drawing checked?
Draw one circle. Go big, and go fast.
How it works
What it can name
The faults, drawn
A percentage on its own tells you nothing you did not already know. These are the separable problems the measurement identifies — each with a different fix, which is the whole reason for telling them apart. Every example below is a real stroke, generated by the same code that tests the engine.
Oval
One axis measurably shorter than the other — your forearm sweeps an arc, not a circle.
Flat arc
One stretch runs short of the rest, almost always where the joint runs out of range.
Ratcheting
The stroke keeps stopping. You steered it round instead of drawing it round.
Tremor
Even shakiness the whole way round rather than in one place — grip and support, not shape.
Not closed
The two ends finish apart. The stroke was treated as having an end instead of being a loop.
Overshoot
You carried on past your own start, with nowhere planned to stop.
Drifting laps
Multiple laps that do not sit on each other — the pivot slid between them.
Cramped
Small enough that only fingers could have drawn it, and fingers cannot make circles.
Two tools, two questions
What this drill looks at
This drill · your line
Measures the stroke itself — how round, how straight, how evenly spaced, how far off the mark, and how the hand moved while it drew.
The number is arithmetic. The finding is not: which fault a set of measurements adds up to, and which fix it takes, is how drawing has been taught for a century. The instrument locates it; the teaching names it.
- Instant, exact, and the same answer every time
- Free and unlimited — it costs nothing to run
- Runs on your device; your drawings never leave it
- Cannot tell you whether the drawing works
Rate My Sketch · your drawing
Coach Luna checks a real drawing — a photo of your sketchbook or a screenshot — and marks the corrections onto the image itself.
She measures technique against what you were drawing: proportion versus your reference, shading, the joins. Never your creativity, your style or your subject — those are not hers to grade.
- Five technique scores, and the single fix to make first
- Three free every day, no account needed
- Generates nothing and never redraws your work
- Slower, and needs something real to look at
The two scores are different measurements and are not meant to agree. A circle can be geometrically excellent inside a drawing that does not work, and a drawing can work with shaky circles all through it. Use the drills to build the hand, use the critique to find out what the drawing needs next, and when you want the rest taught properly — construction, form, light, composition — that is what the Sketching Essentials course is for.
Is this the one you need?
Take all 7 drills and get a profile
About 5 minutes. It names your weakest skill and sends you to the drill that measures exactly that.
How the number is made
What the score actually measures
Roundness
rms( (|p−c| − r) / r )38% of the scoreHow much your radius varies over the whole stroke, against the best-fit circle.
Evenness
deepest run inside the circle − median of the rest21% of the scoreThe worst run of sectors that all fall inside the circle, measured against the typical error elsewhere. The contrast is what separates a real flat spot from a circle that is simply a little small all round. How wide that run is gets reported with it, measured at half the depth of the deepest part — so a broad flattening and a narrow dent of the same depth are told apart.
Steadiness
residual after harmonics 1–317% of the scoreWhat is left once the shape itself is removed. Ovality and a shifted centre are accounted for elsewhere, so this is tremor alone.
Closure
one stroke: |end − start| / r · more than one: widest angular hole8% of the scoreThe gap between where you started and where you stopped. If you lifted the pen, the ends of your path are no longer the ends of the shape, so we ask it of the shape instead: the widest wedge around the centre with no ink in it.
Commitment
how much of the stroke was drawn below a committed speed9% of the scoreWhether the circle was drawn or assembled. Every other measure here reads the shape, and a lap traced slowly on top of the first is geometrically perfect — so a circle crawled round twice could score 99 while the page told you it had been traced. Speed is the one thing that separates a line you committed to from a line you steered, and it is the habit this drill exists to build.
One go
stops counted along the stroke, over the length of it6% of the scoreWhether the circle was drawn or assembled. Every other measure here reads the shape, and a stroke that stops and re-aims can come out geometrically perfect — so a circle drawn in fourteen separate stops could score 99 while the page told you it had been steered round in pieces. It counts stops rather than wobbles in the speed, because a stop is something the hand did and a wobble is partly the tablet: on ninety correct drawings across four levels of capture noise and three report rates, the stop count is zero every time.
Each is mapped through 100 / (1 + (e/e₅₀)^1.6), then combined as 75% the weighted average and 25% the single worst of them — so you cannot bank a beautiful curve to cover a circle that never closed. The top score is 99: below about half a percent of error we are measuring our own capture noise rather than your hand. Every threshold, and the evidence behind it.
The technique
Draw a rounder circle freehand
- 01
Make it big
Fill most of the space. A large circle is driven by the elbow and shoulder; a small one can only come from the fingers, which cannot produce a smooth arc.
- 02
Rehearse it in the air
Hover above the surface and trace the full circle five times without touching down. You are building the movement before you commit to it.
- 03
Draw it in one pass, fast
Aim for under a second. It will feel reckless and the first few will be worse. Speed is what stops your eye steering the line.
- 04
Draw through, do not stop
Go round twice without lifting. The second lap closes the first, and you never have to aim at your own starting point.
Why a freehand circle is hard
Your arm is a chain of hinges. Each joint swings through an arc of its own radius — a few centimetres at the fingers, perhaps ten at the wrist, thirty at the elbow, sixty or so at the shoulder. None of them traces a circle on its own. A circle is what you get when two or more are blended smoothly, at the right ratio, without either one leading.
That is why the size you choose matters more than the effort you put in. A circle the size of a coin has to come from the fingers, which can only produce short arcs joined at angles. A circle that fills the page can be driven from the elbow and shoulder, which are both stronger and smoother. Drawing bigger is not a trick to make the score easier — the score is normalised by size — it changes which muscles do the work.
The second thing is speed, which is counter-intuitive. Below a certain pace your brain switches from running a rehearsed movement to steering by eye, correcting continuously against what it sees. Those corrections are visible in the line as small reversals and in the timing as a stroke that keeps slowing down. Drawing faster feels reckless and produces rounder marks.
What your device can and cannot tell us
The geometry is the same everywhere: a flat arc between seven and nine o’clock is a flat arc whether you drew it with a stylus, a mouse or your finger. The cause is not. A shoulder pivot sweeps a radius of around sixty centimetres, so a phone-sized circle physically cannot be drawn from the shoulder, and a trackpad maps movement relatively, so people re-grip halfway round without noticing.
So on a pen we will tell you which joint is responsible. On a mouse or a touchscreen we show you exactly where the line went wrong and stop there, because anything further would be invention. The gap between your on-screen score and the same drill on paper is real, and it is worth measuring both.
When you have got it
Three attempts in a row above 80 with no named fault, drawn in under a second each, at a size that fills most of the canvas. At that point the circle is no longer what is holding your drawing back, and ellipses — circles seen at an angle, and considerably harder — are the next useful thing to measure.
Questions
Does drawing with a mouse or trackpad hurt my score?
It changes what you can achieve, yes — a mouse has no fine positional control and a trackpad forces you to re-grip mid-stroke. The score is honest about the line you produced, so compare it against your own earlier attempts on the same device rather than against someone else on a stylus.
Is drawing a perfect circle actually a useful skill?
The circle itself, barely. The control it demands transfers to everything: ellipses, heads, wheels, cups, eyes. It is a diagnostic more than a skill, which is why the fault matters more than the number.
Why did my score go down after I followed the advice?
For one fault — tracing — that is expected, and we say so before you try again. The fix is to draw faster, and accuracy always drops before it recovers. We would rather tell you that than quietly fake an improvement.
Why do my circles come out as eggs?
Because your forearm rotates around a joint and sweeps an arc, so one axis naturally comes out shorter. The usual fix is not more care but rotating the paper so your natural arc runs along the long axis.
How many times can I use this?
As often as you like. The measurement is arithmetic running in your browser, so it costs us nothing and there is no cap, no signup and no daily limit.
Why is there no eraser?
Because the measurement is the one committed stroke. Rubbing out the part that went wrong and redrawing it would change the very thing being measured, and the number would stop meaning anything. Undo is there if you want to drop the attempt and start again, which costs nothing — this is unlimited.
Is my drawing uploaded or used to train anything?
No. Nothing leaves your device on this page — no image is sent to a server and no model is involved at any point. The whole calculation happens in JavaScript in your browser.
What is a good score?
A first attempt is commonly in the 40s or 50s. Consistently above 80 with no named fault is genuinely good hand control. 99 is the highest we award, because below about half a percent of error we are measuring our own noise rather than your hand.
Should I use a compass instead?
For technical work, obviously. This drill is about the motor control that construction drawing depends on — the point is the moving, not the circle.
Next drill
Straight line between two points
Connect the two dots. One stroke, and go fast.
Drew something real?
Rate My Sketch
These drills measure geometry. For a drawing with a subject in it, Luna scores five technique dimensions and marks the corrections on your image.