Draw a Circle in Python Turtle: Arcs, Fills and Polygons

To draw a circle in Python turtle, call circle() with a radius:

import turtle

pen = turtle.Turtle()
pen.circle(100)          # a circle of radius 100
turtle.done()

The surprise is where it lands. It’s drawn above the turtle rather than around it, and the next section shows why.

Every screenshot here is a real turtle window on Python 3.12.5.

Drawing a circle in Python turtle

One call does it. The turtle walks the circumference and finishes back where it started, facing the same way, so you can chain shapes without repositioning:

import turtle

screen = turtle.Screen()
screen.setup(640, 480)

pen = turtle.Turtle()
pen.pensize(3)
pen.color("#0b6bcb")

pen.circle(100)          # radius of 100 pixels

print("position after drawing:", pen.position())
print("heading after drawing :", pen.heading())
turtle.done()

Output:

position after drawing: (-0.00,-0.00)
heading after drawing : 0.0

The position and heading printed above are unchanged after the call. That is what lets you draw one circle after another without losing your place.

Why is the turtle circle drawn above the turtle?

This is the part that confuses everyone the first time. turtle.circle() puts the centre one radius to the left of the current heading, not under the turtle.

A fresh turtle faces right, so left is up, and the circle appears above the start:

import turtle

screen = turtle.Screen()
screen.setup(640, 480)

pen = turtle.Turtle()
pen.speed(0)

# mark where the turtle starts
pen.dot(10, "red")
start = pen.position()

pen.pensize(3)
pen.color("#0b6bcb")
pen.circle(100)

# the centre is one radius to the LEFT of the heading, not under the turtle
pen.penup(); pen.goto(start[0], start[1] + 100); pen.dot(10, "green"); pen.penup()

print("start (red dot)  :", start)
print("centre (green)   :", (start[0], start[1] + 100))
turtle.done()

Output:

start (red dot)  : (0.00,0.00)
centre (green)   : (0.0, 100.0)

To centre a circle on a particular point, move one radius below it first. Or use pen.dot(), which really is centred on the turtle and doesn’t have this quirk.

Half circles and arcs with extent

extent is how many degrees of the circle to draw. Leave it out and you get all 360:

import turtle

screen = turtle.Screen()
screen.setup(680, 420)

pen = turtle.Turtle()
pen.speed(0); pen.pensize(3)

for x, extent, colour in ((-220, 90, "#c0392b"), (-40, 180, "#0a7d32"), (140, 270, "#8e44ad")):
    pen.penup(); pen.goto(x, -60); pen.pendown()
    pen.color(colour)
    pen.circle(70, extent=extent)        # only part of the way round

print("90 degrees  = a quarter arc")
print("180 degrees = a semicircle")
print("270 degrees = three quarters")
turtle.done()

Output:

90 degrees  = a quarter arc
180 degrees = a semicircle
270 degrees = three quarters

A semicircle is pen.circle(70, 180). Arcs like these are how you build petals, rainbows and rounded corners, so you will use them more than full circles.

Turtle circle steps: drawing polygons

steps draws the shape as that many straight segments, which turns the same call into a polygon generator:

import turtle

screen = turtle.Screen()
screen.setup(680, 420)

pen = turtle.Turtle()
pen.speed(0); pen.pensize(3)

for x, steps, colour in ((-220, 3, "#c0392b"), (-40, 5, "#0a7d32"), (140, 8, "#0b6bcb")):
    pen.penup(); pen.goto(x, -60); pen.pendown()
    pen.color(colour)
    pen.circle(70, steps=steps)          # a polygon inscribed in the circle

print("steps=3 -> triangle")
print("steps=5 -> pentagon")
print("steps=8 -> octagon")
turtle.done()

Output:

steps=3 -> triangle
steps=5 -> pentagon
steps=8 -> octagon

It’s a neat shortcut: any regular polygon is just a circle drawn with few enough steps. Push steps above about 30 and you’re back to something that looks round.

Filled circles and dots

You have two ways to get a solid circle, and they behave differently:

import turtle

screen = turtle.Screen()
screen.setup(640, 460)

pen = turtle.Turtle()
pen.speed(0); pen.pensize(2)

pen.penup(); pen.goto(-140, -60); pen.pendown()
pen.color("navy", "#ffd43b")      # outline, then fill
pen.begin_fill()
pen.circle(80)
pen.end_fill()

# a dot is the quick way to get a filled circle with no outline
pen.penup(); pen.goto(140, 20)
pen.dot(160, "#0a7d32")

print("begin_fill/end_fill gives an outlined, filled circle")
print("dot(size, colour) gives a filled disc in one call")
turtle.done()

Output:

begin_fill/end_fill gives an outlined, filled circle
dot(size, colour) gives a filled disc in one call

Want	Use
An outline only	pen.circle(r)
Outline and fill	begin_fill(), circle(r), end_fill()
A solid disc, no outline	pen.dot(diameter, colour)
An arc	pen.circle(r, extent)
A polygon	pen.circle(r, steps=n)

Watch the units: dot() takes a diameter while circle() takes a radius. It’s an easy way to end up with a shape twice the size you wanted.

Clockwise circles with a negative radius

A negative radius flips both the direction of travel and which side the centre sits on:

import turtle

screen = turtle.Screen()
screen.setup(640, 460)

pen = turtle.Turtle()
pen.speed(0); pen.pensize(3)

pen.penup(); pen.goto(-120, 0); pen.pendown()
pen.color("#0a7d32")
pen.circle(80)             # positive radius: anticlockwise, centre on the left

pen.penup(); pen.goto(140, 0); pen.pendown()
pen.color("#c0392b")
pen.circle(-80)            # negative radius: clockwise, centre on the right

print("positive radius -> anticlockwise, centre to the left of the heading")
print("negative radius -> clockwise, centre to the right")
turtle.done()

Output:

positive radius -> anticlockwise, centre to the left of the heading
negative radius -> clockwise, centre to the right

That’s the tidiest way to draw symmetrical shapes without recalculating positions. For more turtle drawing, see setting the turtle background.

More Python turtle and beginner guides:

• Python turtle background
• Hide the turtle
• Area of a rectangle in Python
• Round numbers to 2 decimal places
• List comprehension with if else

Frequently asked questions