Polar Graph Paper
Concentric circles and radial lines for plotting polar coordinates (r, θ): roses, cardioids, spirals and antenna patterns. Pick the number of rings and the angle between spokes.
Preview with a centimetre and inch rule. The rule is not printed.
Vector PDF, no watermark. Print at Actual size / 100% so squares measure true (why).
Reading a polar grid
In polar coordinates a point is given by its distance from the centre, r, and its angle, θ, measured counter-clockwise from the positive x-axis. On this paper each ring is one unit of r and each spoke is a fixed step of θ. Degrees are printed every 30°; to work in radians, 30° is π/6, 90° is π/2 and 180° is π.
Angle-from-a-centre thinking reaches well past precalculus: whether tonight’s Moon is a crescent or full comes down to its angle around Earth relative to the Sun, which ahaboo’s narrated piece on lunar phases walks through.
Questions
What is polar graph paper used for?
Plotting equations like r = 2 sin 3θ in precalculus, radiation patterns in electronics and wind roses in meteorology.
Can I get radians instead of degrees?
Labels print in degrees. Use 15° spokes and each spoke is π/12; 30° spokes are π/6.
Why are some circles darker?
Every fifth ring and the outer ring are bold, which makes counting easier.