Algebraic Formulae For The Perfect Checkmark Symbol

25 Sep 2025 · 1 minute read

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In the case that you are required to render a custom checkmark for use in something like a checkbox, the formulas provided below will create a perfect result:

To fill an area where the bottom-left corner is (0, 0):

• THICKNESS = HEIGHT / 5

• A - inner left
  • x = THICKNESS * cos(45)
  • y = HEIGHT / 2
• B - outer left
  • x = 0
  • y = HEIGHT / 2 - THICKNESS * sin(45)
• C - outer elbow
  • x = HEIGHT / 2 - THICKNESS * sin(45)
  • y = 0
• D - outer right
  • x = WIDTH
  • y = WIDTH + THICKNESS * sin(45) - HEIGHT / 3
• E - inner right
  • x = WIDTH - THICKNESS * sqrt(2) / 2
  • y = WIDTH - HEIGHT / 3 + THICKNESS * sin(45) + THICKNESS * sqrt(2) / 2
• F - inner elbow
  • x = HEIGHT / 2 - THICKNESS * sin(45)
  • y = THICKNESS * sqrt(2)

It’s also worth noting that if you are planning to render the above checkmark using a graphics library then you may need to prepend HEIGHT - (...) to all the Y-values as graphics libraries typically consider the top of the screen to be Y=0 and the bottom to be Y=HEIGHT.